• Please review our updated Terms and Rules here

Commodore PET 8296 Keyboard Servicing

S

StowComputers

Member
Joined
Aug 11, 2011
Messages
35
Location
Stowmarket, UK
Hi all,

I'm new to this forum, and glad I found it what with all the retro kit I have! I have tons of questions but won't flood the forums with them all at once.

I have an 8296 keyboard, not used for 25 years I'd say which some of the keys need a firm tap to work. Obviously I don't what to thump the keys and wondered if you guys know if these keyboards respond well to a strip down, clean and re-assembly?

Thanks in advance.
 
Yes, often they respond well to taking apart and cleaning the metal contacts on the board with alcohol. Sometimes you find you need to add graphite to the conductive plunger. It is definitely worth a go if you have the time and patience to take it apart.
 
OK, when I first started off my career in electronics and computers in particular, I worked for this company in Windsor Ontario that made SBCs for Bingo systems. They made the cabinets and the display boards as well.

My job was to build the first generation boards while also doing the (full sized) artwork for the second generation boards (by hand) and to maintain the existing systems.

The cabinets used a matrix of conductive rubber strips to input the X-Y co-ordinates of where the last drawn ball was placed. Now, with all the dust and crap that the blower shot over these strips, they got dirty and unresponsive very quickly and the company's solution was to go and replace all the conductive strips, an expensive and time consuming task.

When I got there, I said "screw that, go down to the local electronics jobber and get me a bottle of Rubber Renue". A quick swipe with a cloth with some RR on it on the contacting surfaces and they worked like brand new strips at next to no cost.

That's what I suggest using on any conductive contact. Apply some with one and of a q-tip and wipe it off with the other. Let it dry for five minutes and the contacts will work like they are brand new (which the surface of them will be).

You can get it at any electronic wholesaler that sells parts for VCR, tape decks or anything else with rubber belts and idler wheels. It lasts forever provided the bottle is tightly sealed.
 
Druid6900 said:
I said "screw that, go down to the local electronics jobber and get me a bottle of Rubber Renue". A quick swipe with a cloth with some RR on it on the contacting surfaces and they worked like brand new strips at next to no cost.

That's what I suggest using on any conductive contact. Apply some with one and of a q-tip and wipe it off with the other. Let it dry for five minutes and the contacts will work like they are brand new (which the surface of them will be).

You can get it at any electronic wholesaler that sells parts for VCR, tape decks or anything else with rubber belts and idler wheels. It lasts forever provided the bottle is tightly sealed.
Click to expand...

Sound like great stuff this Rubber Renue, however here in the UK that stuff is next to impossible to get hold of. None of the US suppliers seem to ship it overseas. The next best thing I was considering is something like this which makes similar claims. This might work for us here in blighty.
 
Can't hurt to just try cleaning first:

Go over the contacts with a clean soft eraser and wipe the board and the conductive pads with isopropyl or methyl alcohol; I've been lucky, it's always worked for me on the PETs (although other keyboards have needed conductive paint or pads).
 
I just wanted to say thanks to everybody for the replies to this thread. I have stripped the keyboard down, short of pulling the key caps off. The PCB was cleaned with isopropyl, then contacts gone over with an eraser. The rubber side contacts were all cleaned and coated with graphite using a 6B pencil. The keys tops were all cleaned in place with swabs and isopropyl. In short, the results are excellent. It all took several hours, but the keyboard now looks and feels as good as new!

Thanks again...
 
I don't know if the pencil graphite is black magic or not but I've had great luck reviving two almost completely non-responsive PET keyboards with the alcohol+white eraser+pencil treatment. The eraser part is the real key. It seems like you could boil the PCB in alcohol and no matter how shiny the contacts look after that they'd be no good until you apply the eraser elbow grease.
 
I have to echo eudimorphodon's comments, I cleaned my keyboard pcb with isopropyl alcohol
and it looked shiny(the gold bits!) but it was not until I used an eraser that took the slight gold
tarnish off the contact areas that it did the trick!

It was definitely the gold pads that were at fault!
 
FYI, I had the same problem with my keyboard on two different machines.
I completeley dissasembled, cleaned and reassembled them and still had the same problem.
I clean the connector tab with an eraser and alcohol.
I was not until I eased the connector back and forth that all the keys started working.
I noticed some depressions in the tab from the connector too.

So there you have it.
 
thread necro incoming...

I have a 8296 and the keys were sluggish and the left shift key did not work at all. Took it apart. Cleaned pads with alcohol and then used the eraser to shine them up. 6B pencil on the contacts and voila! I can type light and fast on it now. All keys now working too.
 
You must log in or register to reply here.
Back
Top