Pro-51 scanner radio keyboard repair?

Probably bubble type and not cleanable.

If it *is* a keymat type employing conductive rubber 'lozenges' and either gold plated print or chemically deposited carbon contacts, as are often used in telephone and remote control keypads, then these can usually - although by all means not always - be recovered using 99.7% or better electronics grade isopropyl alcohol, and a cotton bud (leftpondian Q-Tip).

You will usually find a 'gummy' deposit on the keys that are struggling to work. This appears to be a product of the conductive rubber breaking down. In very stubborn cases, I have effected total recovery, by taking a keymat from a scrap remote control, and carefully razor blading some lozenges off the backs of the rubber buttons. The bad ones that you are replacing can be similarly bladed off, and your recovered replacements superglued back onto the keymat that you are repairing. Obviously, this is a bit of a 'make or break' operation, and needs a degree of skill to accomplish successfully, but if you are committed, and take your time, it's not terrifically hard to do.

Arfa

I haven't worked on that particular model but plenty of experience dealing with RS, Uniden, GRE, etc. Your keyboard problem is typical and can be cleaned if you can get it apart.

The problem is that the keyboard is buried UNDER all the electronics. You have to literally rip out everything to get to the keyboard. If you've never done this before, take lots of digital pictures as you go along.

Looking at the exploded view, it appears to be a rubber keyboard. Disassembly doesn't look too horrible:

I use household cleaner, such as 409 or Fantastic. Alcohol might work, but watch out for solvents that remove the silk screening from the key tops. Don't use aggressive solvents as they're sure to wreck something.

You'll probably find considerable filth around the buttons and in the holes in the plastic case. Clean with a q-tip or brush.

You'll also need to clean the keyboard PCB pads. These are usually gold traces, with silk screen graphite contacts. Wet, smear, and rub VERY lightly. You don't want to scrape off the graphite. Solvents are also a bad idea here.

I noticed that the PRO-51 has the evil square sealed pots for vol and squelch. They're are another headache waiting to happen. If you're getting scratchy sounds when adjusting the controls, dead spots, or erratic operation, it's time to clean these. The problem is that there's no place to inject contact cleaner into these pots. I had to drill a tiny hole in the side and inject oil and solvent with a syringe. Bug me if you want to attempt this and I'll disassemble and photograph one that worked (some did not).

With all sorts of conductive rubber button keys, I have had good results with dry wiping the bottom of each contact pad of the rubber key mat on plain unused copier paper. You need to use enough pressure to leave a carbon mark on the paper and keep it square for even cleaning. You only need to 'streak' each pad an inch or so as the layer of reduced conductivity or contamination is very thin. Take care not to rip the mat. Its usual to be able to restore a dead or nearly dead button to normal operation as long as the button isn't physically damaged.

If the mat is very dirty, get as much loose 'spooge' off as possible with dry tissue then wash with hot water and a trace of dish detergent, rinse and dry thoroughly before cleaning the pads as above.

Plated contacts on the PCB are easy, but the carbon contacts and tracks come off if you look at them wrong as mentioned by Jeff above.

If the buttons are soft rubber then the keypad uses a carbon pad with gold contact points on a pc board. Those cajn be cleaned. I've had my Pro 95 apart to fix the DC jack and thats how it is set up. Many of the RS scanners were made by GRE and I think you can but parts from them.

That's the way I used to do it. It works fine for large carbon button areas, but gives me grief with small diameter buttons. The small carbon button tips seem to have less adhesion. Rub them hard enough and they will break off chunks around the edges.

I've also experimented trying to determine if the connection problem is in the button side, or on the PCB contacts. Although the button may look rough and in need of cleaning, it's the crud on the PCB that really is causing the problem. What seems to be happening is that the rubberized buttons are sweating some kind of oily goo that keeps it flexible onto the PCB contacts. Small pieces of carbon also fall off the rubber buttons, mix with the oily goo, and build up a mound on the contact area. Once the mound has become high enough, there's not enough carbon surface area left to make a decent connection unless substantial pressure is applied. I've found that cleaning the PCB is usually sufficient, but since I'm inside the keyboard, might was well clean off the loose crud from the rubber buttons anyway.

Not dry tissue. Use something that doesn't leave lint all over the PCB, such as a dry cotton cloth (t-shirt rags). As for cleaner, almost anything that removes the oily goo will suffice.

Yep.