IFR1600S with Scrambled Display

[sreaves]

I acquired a FM/AM 1600S at a hamfest today. It has an issue with a scrambled display. The screen seems to display text but there are wide lines in it. I have not had the chance to connect a display to the rear 9 pin connector as I do not have a 9 pin monitor or a 9 pin to 15 pin adapter.

Also how do you get the covers off of this thing?

Any service info available?

Sam
W3OHM

[xmo]

Wowbagger is the expert on these. Hopefully he'll come along and get you some advice.

In the meantime, I am pretty sure the 1600 display is EGA, not VGA, so a 9 to 15 adapter may not help you much. You may need a converter.

[tvsjr]

The operator's manual is on Repeater Builder, it might provide a little guidance:
http://www.repeater-builder.com/test-eq ... index.html

The output is definitely EGA (thus the 9 pin connector) so you'll need a converter to use a VGA monitor. Look at the forums that specialize in arcade game restoration... many of those games used EGA, so they have converter boards available much cheaper than an "industrial" solution (Black Box, etc.)

[Wowbagger]

TO pull the covers: undo the thumbscrews on the back, pull the back a bit, then the top and bottom covers will come off.

Before doing that: what do you mean "wide lines"? Do you mean the scan lines are widely separated? it may be the monitor has gone bad. It's a shame: I've just cleaned out my cache of old monitors.

Can you get a picture of what the screen looks like?

[jry]

you can connect to a VGA monitor ...you may have to sacrifice a VGA cable and use a standard 9 pin D connector.
The display will typically not be able to fully sync but you should see the screen roll by.
Chances are it may be the monitor needing adjustment.

You can pull the monitor assembly and get to all of the adjustments if needed. Some versions need longggggg adjustment tools and others are right on the surface.
Could be the one of the sync frequencies being out.



Just out of curiosity which hamfest did you go to ?

[sreaves]

TO pull the covers: undo the thumbscrews on the back, pull the back a bit, then the top and bottom covers will come off.

Before doing that: what do you mean "wide lines"? Do you mean the scan lines are widely separated? it may be the monitor has gone bad. It's a shame: I've just cleaned out my cache of old monitors.

Can you get a picture of what the screen looks like?

Thank you very much for taking the time to answer my post. It seems that the unit was missing the captive screws and the back plate was simply tight. One of the lock release buttons for the handle is missing and it won't lock anymore. But the big issue is the display problem,

I just posted a picture of the screen on my LeCroy users group. Link Below I hope that this helps. If you can't get it there email me off list and I will send it to you. I could not see how to attach it here.

I was able to get the cover off and a tried the CRT adjustments but none of them affected the screen as far as the problem was concerned. It looks like it is synched (no vertical or horizontal roll. Just looks like some kind of overscan or perhaps corrupted DRAM? I no longer own any EGA monitors so I have no way to test that but I have passed the word to my ham buddies to search their basements.

http://groups.yahoo.com/group/LeCroy_Ow ... 7/pic/list

I think that he problem is related to the video card (slot 15) with the large (Headland HT205) chip on it. If I had a schematic of that board it might help but other than the SIP DRAM chips I doubt that the others are available. If I had a card to swap in there I would be able to figure it out fairly quickly.
Thanks
Sam
W3OHM
P
.S. it was at the Berryville VA Hamfest, our local clubs event. Always the first Sunday in August at the Clarke County VA Fairgrounds. Great turnout this year. I just hope that I did not spend too much on the 1600S!

PPS If you ever need help with a LeCroy scope check out the group. I set this independent group up to support older LeCroy scopes.

[jry]

The 9 pin EGA to VGA connected to a typical VGA monitor will give you a more solid display but will still roll usually veritcally
This will tell you if its the monitor or the graphics card.
from your picture it maybe the horiz sync getting re-trig by noise on one of the power supplies ...bad cap in the monitor.
Assumed you re-seated the cards as well

[sreaves]

I was thinking earlier that perhaps the previous owner did not check the supplies. I did reseat all of the cards. Perhaps I will pull the monitor and see if my ESR meter turns up anything and then look at the supplies. I did find a service manual and have ordered it. Perhaps I will have that in a couple of days. I have to keep looking to see if I have an old EGA or NEC Multisync monitor somewhere.

I believe that the original monitors were made by Sony. Perhaps I can find a schematic or a manual for that somewhere.
Hopefully Wowbagger will chime in once he sees the picture. I'll bet that it is a common problem.

Thanks again,
Sam
W3OHM

[Wowbagger]

Could you post the picture here? I don't have a Yahoo ID and I really don't want to create one.

[sreaves]

It seems that I can not figure out how to post a picture here but I set up a link to a folder on my PogoPlug device that you can just go to and view or download the photo.

I also set the privileges on the folder so you have upload rights there if you have anything useful for me. There is 400GB of free space. I will drop a text file in there as well for you to read. I will leave this link up for a few days.

Thanks,

Sam
W3OHM
Link:

http://ppl.ug/5eLL4j9fzkM/

[Wowbagger]

Sorry, that's blocked by the firewall.

[sreaves]

Wonderful. Do you have some one that can get the picture from the PogoPlug link and get it to you? I have asked the moderator for posting permission but thus far I have heard nothing. I have never been on a board that is so difficult to use. Alternately you could email me at sam dot reaves at gmail dot com
and I will shoot the picture out to you right away.

If you have any other suggestions I am open to that.

Thanks,

Sam
W3OHM

[sreaves]

See if this works please.

http://postimg.org/image/3z8u3z6q5/

sam

[sreaves]

[escomm]

Post a link to the actual picture, not the directory in which it resides

e.g.

[sreaves]

Thanks for that. Sometimes the simple things confuse me!

Hopefully someone has seen this issue. I just got the operators manual from the guy I bought it from. I sure hope I can get this unit working, It appears to be able to do anything that I want to do.

Thanks again for the help!

Sam
W3OHM

[Wowbagger]

Well, that looks like the video card is going south more than it looks like the monitor is going south. I agree that the best check is to hook up to the video output with an external monitor, but the spacing of the lines, the way the background sort-of repeats in them, etc, makes me think the video controller has gone bad. You might be lucky and it's just a bad solder joint on one of the pins of the device. You could try pulling the card and trying to reseat the controller (IIRC it's socketed, but I could be wrong).

[sreaves]

Well, that looks like the video card is going south more than it looks like the monitor is going south. I agree that the best check is to hook up to the video output with an external monitor, but the spacing of the lines, the way the background sort-of repeats in them, etc, makes me think the video controller has gone bad. You might be lucky and it's just a bad solder joint on one of the pins of the device. You could try pulling the card and trying to reseat the controller (IIRC it's socketed, but I could be wrong).

Hi Wowbagger,

Thanks for the confirmation. I found the one source in the world that has the main chip on the board. I had to buy their supply to get one just in case I need it. Unfortunately I do not have a EGA monitor anywhere that I can find to test. If I change the main chip and the Video RAM and some SMT TTL chips that does not fix it I am hosed as the rest of the parts are GALS. Any chance you can get me a schematic or at least a parts list just for this one board. Who do I appeal to at IFR? Is there the off chance they might have a used board from the machines that they have upgraded to newer technology? Also at the moment I don't even know IFR's part number for the assembly.

Any help would be greatly appreciated. Perhaps someone there will need help with a LeCroy scope one day. I can fix those and help with options.

[Wowbagger]

You can make a poor man's converter from EGA to VGA - all EGA does is output 6 bit video - 2 bits R, 2 bits B, 2 bits G - you can make a simple resistor network to turn that into analog, and feed a VGA monitor (as long as it can sync to the EGA scan rates).

As for the video card: Service may have replacement cards, since the older military boxes are still being supported.

And as for the schematic for the board: really, it's a pretty standard EGA video driver, so the GALs are just doing address decode. But as for getting the schematic and the programming for the GALs.... Sorry, I'd have to defer to Service.

[Wowbagger]

http://en.wikipedia.org/wiki/Resistor_ladder

Basically, make 3 instances of a 2 stage R-2R ladder, one for red, green, and blue. You could likely take a DB9 and a DE15 (what some people call a DB15, which is not correct), and make a simple converter in that. It won't be pretty, but it would be enough to test with.

[sreaves]

Hello Wowbagger,

Well I just got the service aka "Maintenance" manual that I paid 75.00 for in the mail. Block diagrams, no detail, not even a PCB stuffing list, a lot less than I expected from wprking on other service monitors for friends.

So I am almost back to square one. I did not see any issues or problems with the connections so I have to assume that there is a bad part on the board somewhere.

I will build up the adapter and give it a shot. At least that will narrow down things a bit. Do you have any idea what the R-2R values should be?

Maybe someone out there has a card they would like to sell or loan for a quick test?

I'll give service a call and see if they can help me.

Thanks again,

Sam
W3OHM

[Wowbagger]

Normally, the lines are about 50 ohms, so I'd try that.

[jry]

for this quick of a test I have never worried about the signal levels going from EGA to VGA ...most of the current monitors will see the signals well enough just going straight in.

The issue is that the scan rates will not match between what the 1600 is putting out and your typical VGA monitor will not sync completely ...usually gets the horiz rate but the vertical will be off.
I currently use a high end converter to go from EGA to VGA that will sync ....the cheap gaming converters will not work on the 1600 output

[sreaves]

Well I have confirmed that the Video card is bad. Here is how I did it. I did not have access to any EGA monitors and I built up a kludge with a resistor summing network and ran the signal into an old Commodore 1702 monitor that I had forgotten that I had.

I had to pop the 1702 open and tweak the Horizontal frequency but it locked and showed me an exact (except for colors) duplicate of the display on the IFR monitor screen. So now my quest it to find another board from someone that has a scrapped unit or attempt to fix this one if I can find the parts and if the chip that is bad is one that is obtainable. The person that I thought had the main graphics chips backed out on me and said that he can not find them in his warehouse any longer so that leaves me hoping that a more common chip is the culprit.

Feel free to chime in if anyone has any further suggestions.

If there is anyone in the near VA,WV,PA,MD that has a working unit and would run a test of my card in his machine to further confirm this I would appreciate it very much.

Thanks all,

Sam
W3OHM

[jry]

before you get too much further I would go to the AUX screen and run the full Self Test. I know it will be difficult to navigate the screens but it looks like you have enough display to get there.
Other option is the serial port but I have never run the diags that way ...may be in the OP's manual though in the remote section.
Give the unit 20 mins to warm up first ...not sure if you have opt 02 the HS Osc
Run the extended test and make sure that it passes and look to see what failed if it does not complete successfully. Some of the failures can be due to adjustments being off a bit.

The reason why I suggest this is so you have some assurance that the core unit is functional before investing much more in repairing it since this is looking to be non trivial at best,

You May be better off dumping it on Ebay as it is and moving on to something else especially if has other self test issues.

I am in OH and if you want you can send me the card and I will plug it in and verify the failure ... should be a cheap and quick USPS but you may want to use UPS so you have a higher level of assurance that it gets here.

Hardest part is getting those XSI!@@ covers off ...one of those things that sounds simple on paper but always seems like a real pain in practice.

Just PM me and I hope the board actually works.

Good luck

[sreaves]

Hi JRV,

I sent PM a while back. You can look back through my posts and discern my email address if that does not work.

Thanks again.

Sam

[sreaves]

Just for the sake of being complete. This issue is solved. In short replacement of the Headland HT-205 graphics control IC fixed the PCB and returned the display to normal. After the video card fix all that remained was a self test failure of the power meter function. The fix for this was simple. I only had to run through the data entry portion of the calibration.

The final problem was an occasional unlocking of the 3rd LO which turned out to be a bad pin on a SMA cable that connected to the module. This was really strange as there were no contact areas remaining on the pin, both sides were broken off. The connector was disassembled (by drilling a small hole near the edge of the top and popping the top off) and the pin was replaced with one from another connector. The original top was replaced and soldered into place covering the hole.

A final tweak of the Spectrum Analyzer amplitude calibration (2MHz and 3MHz filter adjustment) was completed by comparing amplitude of a CW source at a few spot frequencies using a recently calibrated HP8566B Spectrum analyzer.

Although the HP has superior absolute level calibration the IFR FM/AM-1600 tracked the HP very well and was found to be well within specification.

The only remaining electrical issue is replacement of the back up battery (DS1260-100) on the SRAM card. Hopefully the part I ordered will arrive and I can replace it before it goes flat.

Now If I can fix the locking mechanism on the handle I can totally put this instrument to bed!

A general thanks to all for helping with this project.

Sam
W3OHM