Batboard

Hello,

I have become the owner of an IFR COM120A with a display that simply lights up all orange. Upon switch on, a hear the first beep, followed about 4 seconds later with 2 beeps of the same tone in quick succession and then the screen lights up full screen of orange. The heartbeat red LED at the back of the control panel is flashing. I figure the display screen voltages and control circuits, Horizontal and Vertical sync etc must be working as the screen is illuminated.

The Generator Mech Assy and the Synthesizers Mech Assy both have red unlock lights illuminated but I figure that may be not related to this. If I can get the screen working I will attack that problem next. I have checked the main power supply voltages at the output of the supply and they seem reasonable to me but without a circuit a bit hard to know for sure.

Unlike the IFR1600S, I cannot see how to get video out of the unit for an external monitor so I am not sure if it is a screen issue or the unit is not delivering video to the display screen.

Has anyone had a problem like this? It seems quite difficult to find service information. I have taken Wowbaggers advice and written to Aeroflex service to see if they would be so kind as to post a PDF on their site for download. I have also tried to find some information on the Planar EL 569.400 display panel used but even the pinouts on that do not seem easy to find.

Any thoughts very gratefully received.

Kind regards,

Trevor

Short answer - you cannot get video out of the unit. The Planar electroluminescent display is not at all compatible with a CRT, and the video board is not set up to generate video in a format you could feed into a monitor. The fact the display is lighting up suggests the Planar is OK.

Being a A, the firmware for the graphics processor is on 2 EPROMS on the video tray (vs. the B, where the video software is loaded into the graphics processor by the main processor). My first thing to check would be to reseat those EPROMs - it sounds like the graphics processor is not coming up.

Many thanks for that information Wowbagger,

Unfortunately reseating those Eproms did not resolve the issue. I have noticed that on a couple of locations on the digital tray (video tray) a small amount of corrosion has taken place and this seems to have tracked along some copper tracks and moved under a couple of ICs. The corrosion seems to centre around a couple of SMD capacitors. This corrosion is relatively minor and requires a magnifying glass to see but nevertheless it did discolour the solder and did track up the legs of the SMD ICs. I am not sure of the capacitors value as they have lost the value but they seem very like the ones on the board with "VA5" written on them. If I had to guess I would say they are bypass capacitors on the supply rail but without a circuit it is hard to tell.

I have read on this forum that this model had a bad batch of capacitors and assumed they would be electrolytics or tantalums but I then read they may have been SMD capacitors. Does anyone know the value of these capacitors that are on this card with "VA5" written on them?

Any advice gratefully received.

Trevor

Hello all,

As I learn more this problem is becoming more interesting. On the card which drives the Planar panel, I have seen some corrosion which concerns me. These pictures are very magnified as these components are very small and these days with my eyes I can only see this through a magnifying glass.

I wonder is this the problem that is caused by the capacitor problem on these units or is this something completely different.

Many thanks for any advice.

Trevor

Yup - that electrolytic in the last picture spewed... Replace it, clean up the traces, repair what you can.