GRE PSR-500 LCD Display Sudden Loss of Contrast

[seleong]

I purchased a supposed used in excellent condition PSR-500. It had minor battery leakage damage inside the battery compartment in the middle-upper left side (on the black printed warning inside the compartment. Looks like the previous owner scratched some of the leakage corrosion away. I am hoping this did not destroy any of the PCB circuitry underneath the coating!

The scanner worked great for a few days, then suddenly the LCD Display contrast just disappeared. The receiver is still working, still scanning, but I can just barely see anything on the display (Lamp / backlight still works and allows you to see a super light image of the LCD display). All other functions appear to be working - the display contrast is just not there.

I just downloaded the Service Manual for the Pro-106, and am just starting my investigation.

Curious if anyone might have clues / suggestions on what might have happened. No drops, hits, or ESD.

Appreciate any help! Thank you!

Steve KC6IJM

 

[737mech]

Previous owner say if he opened the radio up? You may need to and check the top to bottom board connections. Be careful not to pinch the speaker wire near the top when going back together. Use deoxit or crc electrical cleaner on the pin connectors.

 

[seleong]

Hello 737mech!
Many thanks for your reply! I have not verified if the previous owner opened the radio or not. I will start my exploratory tonight. I need to first see if any traces on the double-sided PCB on the battery compartment side (Linear Board?) might be damaged from the corrosion scraping...
P.S. - like your F-117 photo. I work on the F-35.

 

[tvengr]

Press PGM. Press GLOBAL (F3). Scroll to Contrast.

 

[seleong]

Press PGM. Press GLOBAL (F3). Scroll to Contrast.

Thank you tvengr! I will give this a try too. I just wanted to see if there might be a smoking gun that could have caused the sudden loss of contrast but will give your suggestion a try too!

 

[tvengr]

will give your suggestion a try too!

My contrast is set to 4 and it looks good.

 

[seleong]

Well, I opened the unit last night and hate to say, that I "think" I see some possible corrosion in the area of C383, C361, C365, C355 and only maybe in the area of C394, C388, and C395. I may take a mini q-tip with alcohol to see if I can clean the area at all...
The microprocessor troubleshooting diagram says that IC301 is involved in the LCD circuitry. UGH!

 

[seleong]

Darn! I cleaned up obvious areas of corrosion in the capacitor areas, but no joy (yet). Super sad! I can see where the battery corrosion has migrated into areas under the painted warning label. I will have to really try to clean it up. Maybe a bad investment on my part, not knowing how extensive the "minor" corrosion was. I guess I may have to start looking for another PSR-500 if the display doesn't come back.

 

[gmclam]

You might be successful in running it via a "remote control". I know this is something that WIN500 can do.

 

[DVINTHEHOUSEMAN]

Let the corrosion soak in some vinegar. It should eat it away and neutralize it and you should be able to wipe the remaining corrosion off or scrub it with an old toothbrush or something. This won't necessarily fix anything, but it hopefully should stop it from spreading any further.

It looks like it's reached the vias and probably traveled through them, so I'm not sure what your chances are of saving it. It's possible a component actually failed, too.

If it's still receiving, it would make a great radio for PRO96Com.

 

[tvengr]

You might be successful in running it via a "remote control". I know this is something that WIN500 can do.

Butel ARC500 Basic and ARC500 Pro both have virtual control. It's hard to say if it is a display problem or the data going to or controlling the display on the scanner. The ARC500 software has a free trial period. If the virtual control doesn't work properly, you do not need to purchase the software.

 

[CycleSycho]

.


IF you do happen to 'save' it, remember to periodically check for corrosion happening again. When first damaged, it is more susceptible to repeat corrosion. Good luck!


.

 

[seleong]

Thank you everyone for your excellent recommendations! I think I'll try the remote operation first to see if the radio is functioning normally.
I am fearful of using vinegar on the radio even though it's a mild acid (to neutralize the alkaline battery leakage). I have not separated the circuit card assembly (yet), and only tried to remove/control the visible leakage using q-tips and isopropyl alcohol. My fear too, is that the leakage penetrated the layers of the circuit board through vias and if so, I'm likely sunk. Sad to see a terribly cool receiver taken out by what seemed to be a minor leakage problem.... Thank you again for all your excellent recommendations!
Steve KC6IJM