R2200A no horizontal sweep

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xxx2fan
Posts: 84
Joined: Mon Oct 31, 2005 4:42 pm
What radios do you own?: HT750 Ht1250 CDM1250 CDM1550

R2200A no horizontal sweep

Post by xxx2fan »

I have a R2200A that has no horizontal sweep. Has a dot in the middle of the scope. you can't move the spot with the position control.
Anyone have an idea where I should look any pointers. I have a manual for the unit, But I'm lost on this one.LV power supply voltages check good.

Thanks for any help.
jry
Posts: 481
Joined: Fri Feb 06, 2004 3:14 pm

Re: R2200A no horizontal sweep

Post by jry »

this is pretty straight forward.

You may want to get someone to assist since the manual and access are pretty straightforward.

if the horizontal position doesn't work than it may be the connection between the scope module driver board and the scope amplifier board ...16 pin dip ribbon on the top from the back right of the driver board to the first plug in card in the card cage,


look at pin one of that jumper which has the sweep and position and DC offset( hor pos )

If the dot is centered than the output amp should be OK....may just need to re-seat the connections and the scope amplifier board ....there is a clamp but it has a rubber pad that may have need to be replaced.

these should be a really easy fix....
xxx2fan
Posts: 84
Joined: Mon Oct 31, 2005 4:42 pm
What radios do you own?: HT750 Ht1250 CDM1250 CDM1550

Re: R2200A no horizontal sweep

Post by xxx2fan »

thanks jry I'll check the 16 pin ribbon cable and try reseating the scope amplifier board there is a very small line about 1/4 vertical and the vertical position will not move also if I try the horizontal position it will not move from left to right.
We are going to OBX NC in the morning but as soon as I get back will try the above you suggested.
Thanks so much for getting back to me. Everything works but the scope really want to get it working.
Thanks again for your help
I'll get back as soon as I try your suggestions.
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Andy Corbin
Posts: 158
Joined: Tue Apr 19, 2005 3:46 pm

Re: R2200A no horizontal sweep

Post by Andy Corbin »

I had a problem with the CRT display on my R2400. Turned it on one day and it was way off. Either the trace was all the way to the top of the screen or I could only see a little of it. I immediately thought I would need a new CRT. What I discovered was, I had set my magnetic parts dish on top of the monitor. When I removed it, the trace came back to normal.
xxx2fan
Posts: 84
Joined: Mon Oct 31, 2005 4:42 pm
What radios do you own?: HT750 Ht1250 CDM1250 CDM1550

Re: R2200A no horizontal sweep

Post by xxx2fan »

Thanks Andy for the heads up, I try to keep all my magnetic bowls on my rollaway tool box. Thanks I'll watch where I put them.
xxx2fan
Posts: 84
Joined: Mon Oct 31, 2005 4:42 pm
What radios do you own?: HT750 Ht1250 CDM1250 CDM1550

Re: R2200A no horizontal sweep

Post by xxx2fan »

On the 2200A I re seated the scope amplifier board. I checked the pins on the jumper. Now I have a line at the very bottom of the scope, I can move the trace to the left and right to fill the scope with a bottom with a line if I try to move it up position it will only come up to the 5 and gets wider and but will no move up to center. If I put a scope probe on and touch the probe I get some sort of trace with some vertical at the very bottom of screen but the trace will not move up from the bottom of the scope screen. The horizontal seems to be working ok now. I going to try to post a pic. be my first time with a pic.
thanks for any pointers
cant figure out the pic
jry
Posts: 481
Joined: Fri Feb 06, 2004 3:14 pm

Re: R2200A no horizontal sweep

Post by jry »

understand that that a CRT horizontal and vertical deflection is really just a DC coupled amplifier that has a relatively high impedance and high voltage output.

Just couple a 1khz since wave back into the scope in from the tone out jack and use another scope to trace the signal.

You may want to set the display to external scope and AC couple and see if the vertical can be adjusted.

I would tell you to just disconnect the ribbon cable from the scope and look at pin 1 and make sure there is no DC offset

If you have the tone out jumpered to scope in than you should see a sine wave with no DC offset.

it's a simple circuit on the scope amplifier ...just look at the manual ...connect the jumper back and trace the 1khz signal through to the two outputs ( 180 of of phase from each other or a differential output )
jry
Posts: 481
Joined: Fri Feb 06, 2004 3:14 pm

Re: R2200A no horizontal sweep

Post by jry »

I glanced at the schematic ...pin 1 on the 16 pin is the horizontal / sweep which sounds like its OK

Pin 3 is the vertical drive and does have an offset from the input transistor bias ....look at the schematic.

Set the 1Khz tone level so you get the signal level indicated on the schematic for pin 3 and trace through.

Good news is you have essentially you have two identical amps used to develop the differential output so you can compare to see what has failed .

Issue may not be on the scope amp itself but on the card feeding it
xxx2fan
Posts: 84
Joined: Mon Oct 31, 2005 4:42 pm
What radios do you own?: HT750 Ht1250 CDM1250 CDM1550

Re: R2200A no horizontal sweep

Post by xxx2fan »

Thanks a bunch jry I'll get at it next week and follow your instructions. Will let you know how I make out.
Thanks again for answering
xxx2fan
Posts: 84
Joined: Mon Oct 31, 2005 4:42 pm
What radios do you own?: HT750 Ht1250 CDM1250 CDM1550

Re: R2200A no horizontal sweep

Post by xxx2fan »

removed the A03A03 RTC4021A board. and transistor Q20 fell into my hand.was very careful removing the board, parts ordered my old ECG cross , crosses MPSU10 ro ECG191 have some ordered will let you know what happens when I get parts.
Thanks I'm hoping this is the problem with the vertical.
jry
Posts: 481
Joined: Fri Feb 06, 2004 3:14 pm

Re: R2200A no horizontal sweep

Post by jry »

I would replace both Q19 and Q20 on that board
xxx2fan
Posts: 84
Joined: Mon Oct 31, 2005 4:42 pm
What radios do you own?: HT750 Ht1250 CDM1250 CDM1550

Re: R2200A no horizontal sweep

Post by xxx2fan »

ok Iwill get transistors for Q19 also
thanks for advice.
xxx2fan
Posts: 84
Joined: Mon Oct 31, 2005 4:42 pm
What radios do you own?: HT750 Ht1250 CDM1250 CDM1550

Re: R2200A no horizontal sweep

Post by xxx2fan »

Just wanted to let you know jry
The two transistors Q20 and Q19 fixed the scope works great now. Got them installed half hour ago and been on since. Turned down intensity then turned off scope. Have checked it at times and it is working great.
Want to thank you for your help very happy here everything is working as it should.
Thanks
xxx2fan
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