Aeroflex (IFR) Questions

[hulkinator]

I just picked up a used A-7550 for parts, lid & soft case for my 1200S.

It starts up & goes past the boot screen to the spectrum screen, then after a few seconds freezes up. Can't do anything.
If I hit the Menu button just after the boot screen, it brings up menu, but then freezes.

Any ideas where to start looking?

Scott

Does it mysteriously work pretty much all ok (except a tad off freq) with AUTOCAL disabled? (jumper installed ON JB1 on interface board) ? But normal A-7550 operation is AUTOCAL enabled (jumper JB1 off)...jumper JB1 installed should only be used during calibration procedure...

I had picked one up for cheap. Unit did just that. Recapped supply even with low ESR on all caps...lithium 3v cell was 0.4 or something...so desoldered it...but didnt replace it right away...service manual doesnt say its critical...just it saves memory...

i troubleshooted this for hours..read sm inside out...so odd unit was working pretty much ok with AUTOCAL disabled...with AUTOCAL disabled navigating menus (running out ideas) I noticed accessing STORE function I would lock up unit...more and more was looking like a cpu-memory issue...could that lithium 3V play an important role and needs to be there and good?...does the firmware keep important AUTOCAL or other values in the backed up ram...?

It does!...i installed a plastic lithium cell holder (tight fit with a resistor network close) and a new 3v cell...a couple of ON OFFs and unit is working fine now...with AUTOCAL disabled...100Mhz ref now right down center

Not a unit for serious work anymore but fine for occasional ham & hobby use!

[l30n]

Hello everyone,

I come to this forum to require your help and wisdom.
I am trying to repair an IFR2399C spectrum analyzer.





The analyzer turns on but shows no signal on the screen. Everything else seems to respond correctly (navigation in the menu, keypad, etc).
Opening the analyzer casing you can see 5 LEDs that apparently indicate the state of the equipment. One of the yellow LEDs is lit (middle yellow LED in the image), and one of the red LEDs blinks (the one beside the yellow LED in the image).
There is no IF output signal, nor TRIGGER signal, and the output video signal from the rear connector does not match what was expected. The on-screen signal level is at -106dBm
The calibration signal works correctly (40MHz and -30dBm) but nothing is displayed on the screen, nor is the IF signal at the output of the RF module.
If one removes the RF, IF and Video modules from the analyzer and leaves only the processor module the analyzer indicates the alignment mode on the screen. The odd thing is that when you install the RF and IF modules, the analyzer in alignment mode indicates YIG .... PASS, SPAN ... FAIL, RBW ... PASS, etc. but when I insert the video module and I connect everything in the analyzer the alignment mode is not displayed when the analyzer is started and no signal is displayed.

Could you give me some clue as to what the 5 LEDs mean?
Could you give me some idea where to start testing to be able to repair the analyzer?

I hope you can help me.

Thanks in advance!

l30n

[twbtech]

Hi Guys
I was hoping someone might be able to help... I have a COM120B and it working just fine apart from one small issue that I can't seem to figure out... the unit generates fine on GEN with say MOD GEN 1 at 3.00 KHz Dev and a 1 KHz tone and GEN 2 say 118.8 Hz and 600 Hz DEV, it does what is suppose to do with no problem, in Duplex mode, GEN 1 generates no audio / deviation at all, at any AF frequency / level, GEN 2 is perfect. the COM120B is fitted with Option 4 (Function Gen #2)
Does anyone have any ideas on where to look or has someone come across this one before ??

Thanks

Andrew

[ablitz]

I have 2 IFR1900 1 version 1 the other version 4. The oldest has 1500 hrs and looses time so I think the DS1287 batt is low and options display ???. The other box has 5500 hrs but the time and options still work it's the version 4. Any suggestions as to how ro recover after attempting a cr2032 transplant. All help appreciated
I do have the maintenance manual but it lacks detailed schematics

[ablitz]

Is there a way to copy the DS1287 on IFR1900? I have 2 that will need to have the batteries replaced.

Any help appreciated

[ablitz]

What is the best course of action regarding aging DS1287 NVRAM on IFR 1900s? Is there a solution to copy the existing data and burn it to a new chip so I do not loose options on both?
Both are currently working although one has a recurring Fail on 16 Power Meter.

Any Help apprciated

[k5cg]

I have an IFR 1600S and I'm trying to do a decode/validate for a PL tone on a transmitter (check frequency and deviation). I've been reading the manual and messing around in DUPLEX. I can decode DTMF. I've also seen instructions on the net about the IFR 1200 using the scope and the AF gen to feed the Horizontal at the PL frequency to create a lissajous curve, but I haven't found a way to do that in the 1600 either. This service monitor is an analog "radio shop in a box" and this should be a simple task. What am I missing? Any assistance would be appreciated.
Danny
K5CG

[ljohn6]

Danny the subtone is seen in the AF Counter, Depending on how you setup the lospass and highpass filters will depend on how close it counts the tone. on the Com120 series and 1600 as well as the 1900 which are the ones I have used, the decoders are DCS,DTMF those are the most common used. hope that Helps.
Cheers John

[dcjdinmn2]

I have purchased a Hitachi 30GB, the exact model used in my 2975. I have made what I hope is a successful image of the good drive. I'm doing this proactively in the event I had hard drive problems as I've had them in the past. The image was created with Paragon Hard Disk Manager Suite 15. When creating a backup drive with the image, all seems to work until I browse through lets say the 'default_.sta' folder which has some crazy looking file names and dates '11/18/2107' for instance. Installed in the IFR, Unit boots what appears to be normal with exception of 'siosLib' errors following 'loading X server'. Unit proceeds to boot and appears to operate correctly with only two exceptions. 1) I have lost all options, even after entering the proper s/n as prompted when entering the 'version' screen for the first time. 2) Saved setups do not show up. I can create directories and store files buy they do no show as available for recall.

Now for the bad part. After several attempts I decided to do a diskcopy with the same utility. Triple checking so to not copy from bad disk to good. There was an error while copying from good disk to backup. After the error I noticed the third 'un-formatted Local Disk' partition 7.6GB was missing. Now reinstalling the once good disk results in the same problem with storing/recalling setups (Cant create directory S_dosFsLib_Volume_Not_Available). My options are still available at least. I'm almost sick that in an effort to be proactive and make a backup, ended up causing problems.

When I use FileZilla to browse the /system folders, I do not see anything that stands out as odd. I created a /system/usr/setups folder and placed earlier saved setups in that folder. They are still not visible from the Setup: UI.

I would be so grateful to find at least a way to get my user setup capability back to the original drive. And any ideas from those who have successfully created a backup. I tried SelfImage with no luck either. Forgot what the error was but something prevented me from restoring the image to my new backup drive.

[dcjdinmn2]

Thank You John! If I was to do this over again, using only SelfImage would have saved me from problems. I had noted on previous post that I had problems using SelfImage. I installed SelfImage on another PC, Windows XP laptop rather than the Windows 7 desktop. Worked fine and with what I can tell, made an identical copy. I now have my options available on the backup drive. I still have the issue of not being able to browse 'Setup' files, possibly self induced as mentioned earlier using Paragon Utilities.

I can save/recall setups but must know the setup number I need as I cannot view them from the recall directory/file browser screen.

During boot I get the following errors:
Loading X server...
X11 libs loaded
Xext libs loaded
Xmu libs loaded
Xt libs loaded
Xaw libs not loaded
Xm libs not loaded
Writing log file: S_iosLib_INVALID ID_FILE_DESCRIPTOR
X server loaded

The 2975 then continues to boot, error free. Operation is normal with exception of blank setup recall browser.

[Freddy]

hi

i am a radio amateur and have some questions about my ifr 1600.
i have bought a second ifr 1600 for my testbench.
Unfortunately it throws two failures, sinad error and cwt bandpass error. the solution i found here in the batboard so i could find some bad caps on audio board, now it works great.

but now the questions

what is the difference between ifr 1600 and 1600s. my friend uses an 1600 too but he has an newer version vith the vga tft panel like the 1900.
i have 2 old versions with ega , but software update from 2008. are there big differences from 1600 to 1900 ? what means csa?

the next question , the hand written numbers on the cards crt and power supply have to match in one original machine? my second ifr has 3 mixed numbers , but it works without any problems.

the third question is in the aux menu position 1 calibration, the message is security key is required, how can i get this key?

what parameters can there be corrected?

sorry my english in not so good, an its very very hard to get any parts or information about ifr/ aeroflex in germany.

thanks

[Tech255]

Question for wowbagger.

Hi i did converse with you a while ago about my com120a which has some problems, i am still trying to resolve them but was wondering as they are prone to realtime clock failures is there anything i can do while it still powers up to backup the info stored in the device so i dont lose my options if it does fail.

Also i appear to have a new fault the overtemperature alarm keeps going off when it is ok if you check the battery and temperature sensor section of the settings menu it tells me the temperature is -406 degrees is there a thermistor or other sensor that has failed ?

Cheers.

[jry]

on the 1600 question you are running the TS4317 firmware which used a security key in the microphone connector to access the calibration menu.
There are very few mechanical adjustments on the 1600 series so the calibration menu access is needed to fully align.
You could swap the firmware back to the 1600 commercial versions if you have access to the files.
The later TS4317 was updated to used an LCD/TFT screen and VGA.
The mis matched SN's on the boards means they were swapped around to repair or troubleshoot and as long as they are calibrated together will not make much difference. There are updates to the boards and firmware and some combinations will not pass the self tests. Normally once a unit is aligned I relabel the cards and assemblies.

The 1900 was based on the 1600 and there are major differences between the two including the power and frequency range.

CSA stood for Cellular Support Adapter to add more cellular ( now obsolete ) functions to the 1600 ...externaland optional on the 1600 and internal on the 1900

[jry]

On the COM120 you can pull the RTC chip and read it if you have the right tools.
Those chips are not supported by lower cost programmers so it typically requires a significant investment.

I would check the connections to what I will call the termination assembly which is what I believe that reading is coming from ..sensor near the high power attenuator.
Check to make sure the baseband card is seated but I would suspect leaking cap corrosion on the baseband causing the issue.

To repair leaking caps it usually takes removing other parts and cleaning the PCB

[Freddy]

thank you jry

yes the machine has mixed parts with different numbers, but it woks fine.
yes i know there is many of " mechanical" alignment so i wondered about the menu calibration and what it does.
yes i run the military ts 4317 software and i have no option to change it back, but i dont want, because never touch a running system.
all measurements and functions seem to be ok, i have checked with several other test equipment hf generators, filters, r2001d ,and so on.
i think for home use is no laboratory calibration required, and some Hz Freq error or + - 1 db is ok. i also got a ifr 1100S which i have serviced(Power Supply Dead) and a lot of alignment was to do. i love theese machines but it is very ver hard to find them here in germany. also I have a R2001D with German Rom set, very nice machine too. in Germany Rohde und schwarz is very very Popular very good and expensive. i love american service monitors because they are very easy to use.

thanks.

[Tech255]

Jry.
Thanks for the reply about the 120, i am in the process of repairing the baseband card i will be replacing all electrolytics and a fair amount of the 100nf ceramics as they seem badly corroded also one of the 78l05 chips is bad as well.
It will probably take a few weeks of careful cleaning and resoldering to sort it.

So if i read the dallas clock chip and store the info does it just program straight back in and will work and keep all my settings.

[Tech255]

Wowbagger.
Not sure if your still monitoring this but if you are i have a question regarding my com120a.

I have spent quite a long time repairing the baseband module ive replaced all the electrolytics and about 60 100n ceramics and several of the op amps and regulators also a fair amount of through holes have been redone but out of the 4 problems i had only one has cleared the rf level meter now passes self test but i still dont think it works the distortion and sinad still fail and the alarm for overheat on rf input still shows although i have found a way to defeat it by removing the sensor wire from the rf block.

I now have a full maintenance manual with all circuits it seems most things go through a 4051 switch ic then an op amp and into the a to d converter this is where i come unstuck, i have built a card extender so i can work on the board out of the unit presumeably after signals enter the a to d software takes over to decide where they go and what shows where are there any test functions you can enter to switch different bits on and off to aid diagnosis as theres no circuit descriptions in the manual.

[jry]

I would pick one of the issues or self test failures to work on .

Verify the functional blocks of the unit separately like the Distortion Meter ,DVM , SIgnal Gen, audio gen and Monitor/modulation.
Go through the calibration process and see what doesn't calibrate.

The Distortion SINAD self tests loops through everything.

The over temp sensor LM35H may be bad ...should be .25V at room temp out from the power term assembly.

If that is correct than there is something else on the baseband but I suspect the sensor. It is probably putting out more than 1V

[Tech255]

Jry

Thanks for the reply the temp sensor has about 200mv coming out of it if i warm it up with the hot air gun it starts to move up to about 400mv and then drops down the data sheet says about 10mv per deg so that seem alright to me.

Even though the rf meter now passes it still does not show any rf level i cant calibrate the power levels i dont have a suitable rf source with the required amplifiers.

The distortion and sinad dont seem to want to calibrate i know its generating the correct level because i can monitor it on my marconi 2955.

Unfortunately the manual ive got has some quality issues on the baseband circuits a lot of the wording is blurred so im having trouble following where things go between the pages, but i will percevere.

I am just in the process of making another card extender but with the socket at right angle on the top so i can lay the baseband tray down on top of the others and still work on it makes it a bit more stable the one ive got now is a bit jerry rigged.

Ill let you know how i get on.

[jry]

sounds like the temp sense is OK.

See if you can calibrate the DVM.

You can get close enough using some known power levels from another signal gen and radios on the power meter. Not really calibrated to spec but will get you operational.

Sounds like you have still have major issues on the baseband card.

I would almost start by troubleshooting the over temp since that is relatively static.

The processor will sample the signal and measure all the time.

chase that through the baseband card since you can disconnect to see the level change through the process.

[Tech255]

Jry

Ok had some major success today i got my new extender board built enableing me to work on the baseband card with it laying on top of the unit, i followed the alarm signal through the system until it gets to pin 1 on the large ADC ic this is where i thought i was going to have trouble.

But after looking the rest of the circuit over i noticed there is a 4v reference signal goes in on pin2 theres a test pin to check it, and it wasent there.
Its derived from 2 8pin ics to the left of it 7.5v goes into the 1403 ic which is then fed into the op177 which has a pot to adjust the reference voltage the 1403 seemed ok so i replaced the op177 and bingo the ref voltage re appeared.
This has now cured the alarm signal and it tells me theres 23.8 deg rather than -406 deg i was getting.

On the power meter side of things i went into the cal menu and did the zero cal with nothing connected and it now reads the output from the marconi which is only 1mw but it shows that correctly i also tried my baofeng uv5r and it gave me 4.3w which seems to be compareable with the marconi, i will try one of my larger rigs when i have space on the bench.

Something has changed on the distortion and sinad section i use the marconi as a monitor for the calibration and although the ifr is generating an audio signal it dosent seem to be giving me anymore than 0.6% distortion and on the sinad its 43db so neither of them will calibrate so looks like ive got more to find will be back on it tomorrow.

[Freddy]

Hi

I have some questions about the pl 1536/ grm which was mounted under my IFR 1600.
I have no use for this "special" box but insinde is a wideband amp i think. There is a motorola mhw591 rf module, and
a push pull amp stage with motorola MRF146 which is a rf wideband transistor. I think -10 dbm perhaps 0 dbm should give some Watt output. My problem is there is no documentation /service manual to find. It would help me a lot to know the Voltages and the pinout of the conector on the module on the right side. It is the 8 pin connector.

thanks - Freddy

[jry]

Look at the TS4317 service manual on the repeater builders site. the amp schematic is there at the end

[Freddy]

OK thank you JRY i found it in the mil service manual.


1 +5 volts
2 on off
3 band control for switchable band pass
4 ground
5 +15 volts coupled to pin 6
6
7 power monitor 1,5 volts + - 0,5 volts
8 - 15 volts

this is for the broadband amplifier 83A1A3 RF Amplifier mounted in some special boxes for military "uut" The "5 watt amplifier"
it is mounted in my pl 1536 grm

[ablitz]

When i powered it up the display was upside
down and there were horizontal lines all through it. I turned it off and much later turned
it back on after plugging it back in to MY UPS power and it was working fine.
Perhaps a power supply issue?

Sounds like the actual LCD panel got a glitch when you switched it on, glitching the lines that control inverting the display and the display scaling. When you switched off and back on it reset.

That's a weird one - I didn't see that behavior when we first did the conversion from the Trinitron bottle in the 1600 to the LCD on the 1900.

I have 2 IFR 1900s ver 1 & 4 only saw this issue with the ver 1 and it usually goes away after 10 min but thanks to posts from others i bought a Chinese LCD just in case. Contact me if you need help.
Andy

[ablitz]

Hello all
I would like to propose an IFR 1900 topic area if anyone is interested. I bought 2 1900s and have spent more than a year refurbing and appreciating them to share experiences. I read a lot of threads and would love to hear from the people that worked on these innovative systems. Having spent more than 50 years in communications this forum has helped me immensely and i want to thank you all
Andy

[ablitz]

Hello all
I would like to propose an IFR 1900 topic area if anyone is interested. I bought 2 1900s and have spent more than a year refurbing and appreciating them to share experiences. I read a lot of threads and would love to hear frombthe people that worked on these innovative systems. Having spent more than 50 years in communications this forum has helped me immensely and i want to thank you all
Andy

[giancom120b]

Hi to all,
the ifr 1900 whats frequency range?
I have seen video on youtube...ifr 1900 receiving at 7.080MHz ...

In datasheet spec start frequency at 10 MHz...

How is it possible?
Real frequency range?

Best regard
Gianfranco

[ablitz]

I have used mine from 400KHz to 2GHz although the specs state 10 MHz to 2010 MHz

[fineshot1]

Hello all
I would like to propose an IFR 1900 topic area if anyone is interested. I bought 2 1900s and have spent more than a year refurbing and appreciating them to share experiences. I read a lot of threads and would love to hear from the people that worked on these innovative systems. Having spent more than 50 years in communications this forum has helped me immensely and i want to thank you all
Andy

This would suit me fine - I have a 1900 as well

[ronbot]

First... full disclosure...
I'm a calibration tech at a Cal Lab in Missouri, and the question is regarding a customer unit... BUT, as a Ham since the 80's, I've grown very fond of this thing in a very short time... and have already started the hunt for one for myself!

We're a full-service repair/calibration facility for all major brands, mostly servicing avionics test equipment. We usually don't have any problem getting service/maintenance manuals, but I tried to get a service manual on this from Cobham/Aeroflex/IFR..... and their response was that it's obsolete, no service, no parts, no manuals available.

The problem is to do with the DVM when using the Scope/DVM input connection... the AC frequency response rolls-off above about 2.5 to 3kHz... down by 3dB at around 8.4kHz, -6dB at 20kHz. The test spec says it should be flat up to at least 20kHz. The oscilloscope has the same symptom.

When using the Audio/Data/SINAD input - no problems... flat response out to 160kHz. Ext MOD input is flat out to about 40kHz.

Can anyone verify the frequency response of their COM-120B/C Scope input on DVM or oscilloscope mode?

Anyone ever find a service/maintenance manual? (willing to pay!)

The baseband board appears to have been made after the worst of the capacitor plague, as the caps test out acceptable (I pulled a few samples and tested value and ESR... I have PLENTY of experience with replacing small aluminum electrolytics on other products... uggh!).

S/N 500101xx
Main Program: V 4.15 Nov 2 1999
BIOS: V 4.10 Nov 2 1999
GSP: V 4.14 Nov 2 1999
Keyboard: V 3.01 Jun 30 1995
DSP: V 4.12 Nov 2 1999

[AdrianH]

Hello to the group new member on here, I have been reading these posts about IFR and have found them of great help. I thank you all for providing the information you have.

I am now the owner of a faulty Com120B, , when I say faulty I mean that sometimes the unit will power sometimes not, sometimes I get keyboard error sometimes it flashes on the screen a warning to say signal overload, which is good when nothing is connected.

I suspect the unit has been dropped and there is some bad joints/possibly cracked track or just loose connections some where in the set, when it does power up it has gone passed initialization and even passed self test, so it does show promise, even though it does not do that often, yet!

I was in a bit of a panic after reading about loss of RTC battery/clock where the serial number can be lost and all options, the unit was last powered in 2010 but when i managed to get it to start the clock was 30 minutes out.

I have taken a photo of the versions and Options list as here, and will try and find something with a serial port to record serial and option data as previously mentioned in one of the messages.

If @Wowbagger is still around, may I thank you for your input to the thread and I wonder if you would remember our company here over in England.

We wrote the MPT1327 software for the units, under the head Software Engineer called Tom Johnson.
That side of the company has long gone and Tom is now freelance with his own business, there were others Phil, Andy and Dave that all did software and could all have had their part in it.
I know nothing about the software apart from knowing it was all happening back then.

Anyway I may be smelling hot PSU time to switch it off.

Cheers

Adrian

[ablitz]

Greetings Adrian

I have 2 IFR 1900s and there are 2 ds12887 battery clocks. I decided to mount a cr2032 battery holder and grind down the side of each chip to expose the internal battery to save the data. In all i was successfull and found that in one unit both batterires had about 1 volt remaining which caused the rtc to loose time. After i solered everything up, i cut the strap to the internal batteries and reassembled.Both IFRs came back with all original options working no errors except the options listed 0 in both. All is well since. I also found that after i cleaned the board connections, intermittant faults stopped. There are several pictures on the Internet on how to mod the chips. I plan to upload my pix very soon but thought this would help. Also do check all power caps especially tantalum. I think my untis ver 1 1997, and ver 4 1999 are past the bad cap issue. Hopefully Wowbagger is monitoring and he can be more helpful. His wisdom and knowledge has helped me with my boxes.

[AdrianH]

Hello ablitz
Do not think I am into grinding down chips just yet.

I have had the unit powered up for 5 hours now, I reseated all the cards straightened the side chassis, not bent that much just a bit buckled and when I first powered it on this morning it passed self test. As times went on the signal from it became more and more noisy. About an hour ago I did another self test and it failed on Deviation and Distortion meter.

I believe I read from this post about checking Caps so i pulled the Base Band tray and yes there is corrosion starting on the board and leakage around the base of some caps.

Now I have not done much surface mount work in the past so this will be a learning curve for me both sourcing these caps and replacing them. Counted 52 in total on the board, so starting to get a shopping list together initially for this board and will also look at others.

I do need to ask about them and that is the labelling of them Some are marked

H4
47
16V

On the Digital Board i have some:
g3
47
16V

Are the H4 and g3 just batch codes or are they a rating?

I know thw 10 16V will be 10 uF and 16 Volts. It may just be a case of what I can get hold off but would like to check first.

For a 20 year test set I would expect problems with capacitors, I needed to do similar on an old Rohde and Schwarz SMFP-2 I have, but they were normal wired electrolitic's.

Cheers

Adrian

[Tech255]

Adrianh
I have just repaired my baseband board i replace all the electrolytics and about 50 .1uf ceramic caps also quite a few of the 8 pin ics and several others i still have some faults.
I do have a service manaual but some of the baseband diagrams are a bit blurred.

[ablitz]

Just use the values not sure about H4 or g3 but i replaced everything with tantalum caps on the signal and electrolytics in the PS. Hopefully ther will not be a lot of corrosion under the leaky caps. Do you see any dates stamped on chasis?

[AdrianH]

Hi;
I have replacement caps on order, some flux off, some solder paste and I will have to dig out my anti-static work mat.
The main thing that is worrying, is I do not know how long the RTC will last and could I make it worse? I found an old device with a serial port so have taken the readings as suggested, but it looks a bit like Wowbagger is no longer active, so I would not be sure who to ask if they go. I do hope Wowbagger is OK, and I would imagine being questioned all the time would be tiring.

I do have manuals, but they are not going to provide the information needed for this task should the need arise.


I have nothing to scan these with, which is a shame. But I can take a pic of the odd page if required.
I guess I have nothing to loose, I got it as a faulty unit.

I will have a look for a date stamp, do you know where it would normally be?

Cheers

Adrian

[Tech255]

Adrianh
What part of the uk are you in i have got a laser scanner copier if it helps, where did you manage to get an original service manual from.

[AdrianH]

I am in the Blackburn area. North West. I got it from work with the test set as mentioned in one of my posts the company I work for wrote the MPT 1327 software.

I could scan it at work, but a bit like taking the Mick.
I find the manual a bit awkward as there is no descriptions, multipart drawings and not the clearest of documents, a bit like it is copies of copies of originals.
I will sort something eventually.

Adrian

[Tech255]

Adrianh

The copy of the manual ive got is a bit like that but the component layout is not too bad so ive written loads of stuff on they do take a bit of time to understand and im still not totally sure i understand them. I also have deviation and distortion problems you need to go to page 100 in the baseband circuits there is a notch filter, ive got signal going in but nothing coming out i have replaced the filter ic but still nothing i know its something around there but havent traced it yet. You will need an extender card to work on it in circuit.

[AdrianH]

A bit slow progress tonight, started to replace caps starting with the 100uF 6 Volts, then the 47uF 16 Volts, going smaller as I go. Well that was the plan!
Then it changed. I did the 5 x 100 uF's, then 1 x 47 uF that was leaking and the 3 x 1 uF that were also leaking. Had a good clean of the board, tested the new caps were not short, plugged the board back in and powered up. Need a bit more natural light to work with the bench light gets to my eyes.

A few things I have noticed several times before is that it 'Restores cals to front panel' and then gives me a keyboard error. Power it off and back on again and do not get the same message or keyboard error. Keyboard works, do a self test and everything passes.

Is there another battery as well as the RTC clock battery could that be failing? With the RTC potential issue I have tended not to remove a lot of cards yet, so guidance appreciated.

Cheers

Adrian

[ablitz]

Greetings Adrian

Im not sure about the Com120 but the IFR 1900 csa has two. One is for the service monitor itseft, storing options and rtc, the other for the cellular section. I think yours has one hopefully ds12887. The ds12887 is y2k compliant, whike the ds1287 is not. Unfortunately I have not found a chip burner that can copy either chip

[AdrianH]

@ronbot

This is probably to late for you now, but as I am getting things to work, thought I would try to help out. I put in a signal from a DDS generator at 1kHz sin going up to 20 kHz, checked it was reasonably flat on my R&S kit then plugged it into the IFR Com120B and also found it flat across the range on the Scope/DVM in socket.

Here are two picks the first at 1kHz and the second at 20kHz just to show what my non cal'd unit was showing. This was just at me setting a level around 1 Volt p-p not at any set level out.


I was going to use my old SMFP2 for the sig gen until I found that the output is bad, looks like an output stage is shot, I only get half a sin wave

Hope it helps.

@ablitz

On the subject of the RTC devices and programming or backing up data, I was wondering about the following for the DS1286 and possibly others?

I have a Genius 540 Eprom/prom/eeprom programmer one of the cheap Chinese things that plugs into the USB port.
Is there anything to stop me making my own adaptor so that it looks like an old fashioned 64 Kb eeprom like the Atmel AT28C64B, the pin out's are almost the same, do not connect or connect to pull downs the unused address lines from A6 to A11 and leave pins like the sqr wave out disconnected

And sorry to the mods as I realise all my posts need to be checked before they are active.


Cheers

Adrian

[AdrianH]

Just in case some users of the 120 series do not have this:
https://ats.aeroflex.com/support/techni ... est-setups

The above is a link through the Cobham website to a software utility that loads a few utilities on the Com120B/C
You do have to have a login to download the file but it was a simple on line form, click which updates you want or un-click them all if required and get you logon.

It is a Windows package I loaded on to mine using a serial lead to take between the PC and the Com 120 serial port and away you go.

I could not find easyscan/track or anything else and guess this could disappear at any time.

Next I have a question regards the back panel, there are two adjustment pots, one viable 'A' and one 'B' not unless you take the rear panel off, both on the PSU section, but no mention of what they are for setting. So before I go playing can anyone suggest what they could adjust?



many thanks

Adrian

[AdrianH]

Since I posted the above in the morning and now it is late evening for me, I decided to have a play with the pot one can see, very carefully.

It did modify the +10.5 and -10.5 Volt ranges, it seemed to be a balancing act as one moved so did the other, as the tolerances are different between the rails for example:

The -10.5 Volt rail is -10.5 Volts +/- 0.5 Volts
The +10.5 Volt rail is +10.5 Volts +/-0.25 Volts

So I settled on
-10.8 Volts and +10.3 Volts. As I took the +10.3 closer to +10.5 the neg side went closer to -11.0, so that seemed to be my compromise.

The other rails are very close to the cal doc so I am leaving the other hidden pot alone. but is someone can confirm what it adjusts as it would be a nice to know.

On the digital card there is a green battery 3.6 Volts, I assume that is for the NVRAM as it seems to occasionally losing cal data, (it's out of date anyway).

The RTC was made in 94, how it is still running is anyone's guess, that is my major panic.
Anyway thanks to the mods for your assistance.

Adrian

[ronbot]

Adrian, those screen pix are EXACTLY what I needed - I now know for certain this unit does indeed have a roll-off problem with the Scope/DVM input.

The weird thing is that I've drawn a partial schematic of that "Audio" board (the one with all of the BNC inputs), and there seems to an "always in circuit" low pass filter.... I'm really struggling with this now. (Does ANYONE have a schematic of that board??)

If you measure the DC input resistance of that BNC, with the unit ON and that input selected in DC coupled mode, does it have around 1M Ohm input resistance?

Also, do you know how to access/change the Scope Vertical resolution/scale? I can change the Horizontal scale, but not the Vertical.

Ron

[AdrianH]

I was sure I posted again after asking about adjuster A and B?

I found that A adjusts the +10.5 and -10.5 Volt rails, so assume B could be similar poss for the 5 Volt rails but decided against adjusting as they were OK.
Can any one suggest where the eeprom is that goes faulty around the front panel, the Message I keep getting 'restoring Cals to front panel' follows on with a Keyboard error that I have to switch off and then back on again to resolve. If it is something I can replace I would look to doing this but not sure if on the Digital Tray of the actual front panel?

Cheers

ADrian

[AdrianH]

OK second time around, I could not edit my previous post but wanted to change it in case others that followed possibly went down the wrong path with my ramblings. So that post has been deleted and I have added this.

I thought I had found the EEProm on the front panel that was causing the 'Restoring Cals to Front Panel' message and then subsequent keyboard error that locked the keyboard, I would then have to power off and back on again.

But with help from another forum member I have been pointed down to a more obvious possibility.

Originally I thought it was a 26V12H electrically erasable PAL programmable logic device, but it was pointed out that the 8 Bit processor a TMS370C256 also holds 512 Bytes of EEProm and that this can be used to hold information as used in some car radios etc. Now this processor is romless and therefore has a good reason for the 512 Kbyte OTP rom next to it.

In which case the program being held external (I hope) means the processor could be replaced with another without loss of program?

The main reason for the uncertainty is the service manual does not hold circuits for the front panel processor, or the front panel audio board, it just has a few overlays and high level block diagrams.

So thanks to Tech255 for the assistance.

Adrian

[drb235]

Hello, I have a ifr com 120A and I was wondering if there is any way to get the serial number out of the unit. I have tried to connect with a serial cable and a terminal program with no luck. It has the sticker on the back with the serial number on it but I want to know that it is still programmed in the unit, thanks in advance, David

[AdrianH]

Hello David;

I can only suggest a couple of things for you.

If you still have options available under your /setup/version/ screen then there is a good chance you still have the serial number in there.

But must admit I am unsure of the differences between the 120A and the 120B as to capabilities.
I have the following set on my serial screen:
Operating mode :Host
Baud rate:9600
Data Bits:8
Stop Bits:1
Parity:None
Handshake:CTS/RTS
ECI Echo:ON
RCI Control:ON
Handshake off threshold:24
Handshake On threshold:1176

I have the following set in Hyperterminal
Baud rate:9600
Data Bits:8
Stop Bits:1
Parity:None
Handshake:CTS/RTS

The cable I connect between them is a one to one for every pin male to female

And that just works OK for me.

From there running Wowbaggers RS232 checks and if you still have a good RTC provides the serial number & an option number. if serial number comes back 0 and options 0 you have a flat RTC battery.

What settings, lead and software are you running to try?

Adrian