Having had to service many TV remotes, game controllers, and other things with the silicon/carbon pads like you found in that keyboard I have discovered that paper is abrasive enough to take the sheen off the pads. It's cheaper than the sandpaper and removes far less material thereby preserving the lifespan of the device. For pads that are a bit more difficult you can use IPA as a cutting agent by simply lightly wetting the paper and dragging it across the pad. For tarnished contacts on the circuit board a pencil eraser works wonderfully. Just be sure to thoroughly clean them with either IPA or denatured alcohol.
I always thought "digital basement" was just something you thought up. Until I saw the furnace, I never thought you were literally, in the basement. Great videos, keep them coming! Repairing electronics is always satisfying!
his furnace resembles a minicomputer or small mainframe with a pipe sticking out the top more than an actual furnace :P if it weren't for the pipe... :P 'oh look it's got papers sticked to it with the password' and 'don't turn this off'
I simply use normal paper for "sanding". These rubbers behave like normal rubbers you use with your pencil. First they leave a dark stripe on the paper, after a few times, the rubber stops making those heavy stripes and thus is cleaned. I believe this methods is less aggressive than sandpaper. Love your show, keep on rockin :)
By 8 years old I was an expert at fixing buttons like this thanks to my Atari 5200. Personally I don’t bother with the sanding process I go straight to the carbon paint repair. That has yielded the best results for me. Besides my 5200 joysticks it also fixed my C128Dcr keyboard. Mind you this is the worst button design ever and I don’t know of any permanent fix but the paint technique has the advantage that it can be applied multiple time where sanding may only work 1 or 2 times before the conductive layer had been completely removed.
"It's hard to type on this type of keyboard" For 12-year-old me it was the perfect thing to learn how to type. And I still remember how I hated the keyboards of other machines where you had to hit Shift all the time to get to the characters that were important for BASIC programming such as the double quote. I felt that those grown-up keyboards did nothing but slow me down :-)
just a tip on those carbon rubber pad button repairs: i had lots of cases where cleaning and sanding didnt help or lasted anything. but what really worked for me excelently was a rubber pad repair kit you can get from ebay and such, usually for remote controlls. they come with new carbon rubber pad plates , different sizes can be purchased and silicone glue. given there is enough room between the exiting rubber pad and contacts on the pcb, you just put a tiny bit of silicone glue on the old rubber and put a new pad on top , then let it dry over night. buttons i repaired with this , then worked as new and has been more sensitive, since the lesser distance between new pad and pcb. if you have a rare case where the spacing is a problem, youll need to take off some from the old pad before glueing the new pad on top. some just "cut", some "grind". i never needed to do this however.
Really like the shorter intro, very retro looks like you did it with an Amiga and Video Toaster. I told you the PET had a bad RAM chip. The last time I tried to fix it was before the internet though and couldn't find any chips, much better now with the internet. The old gal is really starting to look good almost like new. Thanks for making these videos!
Hey Adrian there is also a conductive paint you can purchase to rejuvenate the carbon contacts on the key plungers. Should be able to locate it in a good electronics store.
Hi Adrian, If the screws go into plastic you can fix the hole by putting super glue on a toothpick and rubbing it on the inside of the plastic post reducing the diameter of the hole.
I am sure you've been seeing us in the community going back and forth on Twitter, YT and FB about heatsinks so I am glad you addressed this. I posted the link of the heatsinks on the Commodore 64/128 group so everyone can get some. Thanks again!
If I may add my two cents... While I've never repaired a computer keyboard, I have on several occasions repaired the very same rubber contact pads on tv remotes and calculators. In this case it's usually the volume up/down and channel change pads that wear. The rubber contacts I repaired were well beyond the sandpaper method so I had nothing to lose. I placed a tiny drop of superglue on the rubber contact then a tiny piece of aluminium foil onto the pad. Once the superglue cures just trimmed off the excess foil leaving a nicely foil covered pad. Never had a problem again with either the remotes or the calculators. I imagine it would be time consuming to do this to an entire keyboard but it might be worth considering if the keyboard still won't work right.
I had a similar problem with recessed battery contacts in some cheap stuff. Took sandpaper and used a bit of glue to stick it to a small rod, then cut out the circle of sandpaper, so I could get down into the holders to clean off the green crud on the bare brass. Would probably work for you using some cheap wooden dowel rods cut to size, and then make a few with sandpaper stuck to both ends. As they wear simply turn over for the fresh paper, and then cut off the used paper later and replace.
Typing anything on that keyboard would drive me crazy! I have a Timex Sinclair 1000 and I won't even turn it on because the keyboard makes me crazy. Now that 4016 PET? That is a thing of beauty!
On the keyboard contact cleaning, you might try gluing small pieces of sandpaper to the end of a dowel or a pencil eraser so you can simply spin the dowel on each contact, thereby avoiding the need to press each key and also sanding the membrane.
Nice Job! One thing I just love about the pet: that style of monitor casing, looks just excellent retro (reminds me of 80's Sci-Fi movies ^_^). Having a character set with some graphics, you could at least make a quarter character "pixel" art for images or games, and in 8kb writing in ML is probably most efficient and speedy.
Oh, I love the intro! You know, for a crossover event, if you ever go back to your Commodore 16 and have it upgraded to 64 kB, you should play Pets Rescue on it.
With how easy the PET series was to open, and service, I wish Commodore had offered an all in one model of the VIC-20, and C64 in the same style of casing with a color monitor as an option.
@@IanThatMetalBassist Yes, I remember that one, but I'm talking a more consumer commercial model with full color screen, as I've only seen the Educator 64 with green screens.
@@CommodoreFan64 I wonder how difficult it'd be to do a CRT swap with a color tube. That's assuming that the motherboard isn't modified to only output monochrome.
Adrian, when using that 1500 grit or virtually any fine wet/dry, on something like that rubber/carbon matrix use some liquid as a surfactant like soapy water. It won’t hurt the material (obviously not for sensitive surfaces) and the paper will work more efficiently and leave a better surface. Cleanup of that rubber would be a simple rinse and dry. Try it out.
ADRIAN BLACK, When writing a Diagnostic program like C64 or other arcade games how do they "Ping" check and test each RAM chip, ROM chips, etc? The Diagnostic program would have to know the address mapping decoding but how does it test each RAM chip and ROM chip?
If your ram chips keep going bad, sounds as if there is something making them go bad. Try checking the caps, esp the decouple one. Also if it happened when as in the video you change the keyboard then look at the caps round that interface too. I also believe that SRAM is very sensitive to static. Also the PSU has very big resevare caps that may be holding a charge for longer than you think and so you might be changing/working on things while there is still current in the circuit. Try discharging them befor doing any work
A little bit of rubber rejuvenate then put in hot water with a little bit of dish soap. You must get the rubber soft. Then you can sand it a little bit.
Tip for those fixing those carbon pads in keyboards or remotes, dont use sand paper, use a regular sheet of copy paper and rub each key on the paper, it saves a lot of the pads and dosent take off too much. Something i have been doing for years with great success.
Oh yeah, finally I could see my favorite computer beeing restored :D I actually have a PET 2001, sadly not a blue one, but it had the same problem, and what I did with the keyboard, is that I stuck some aluminium tape on the rubbe lr plungers, btw you can take out the rubber part, and it works perfectly, even today. Fun fact: you can test 2114 SRAM in the VIC20, it makes live a lot easier and doesn't harm the PET, since turning it on multiple times in a short period of time can cause some damage in the CRT, thats what I've heard.
This fix should mostly be permanent. The rubber these plungers is made of is mixed with a carbon compound. All you're doing it exposing a fresh layer where oxidization has occurred. I say mostly permanent because without maintenance everything eventually fails again.
Gluing a pice of aluminum foil to the bottom of the rubber is a surefire fix if the button travel is enough to open the circuit with the foil in place.
Have you ever thought that you may be zapping your chips with latent static damage. They will work for a will but damaged area eventually fails later in time.
I think what little diode is is a reseller of chips bought in bulk. they sell them in small counts because no single person needs like a thousand of those chips. though now I'm curious if one can make a logic-free (possibly even pin-to-pin) adapter for SRAM chips still manufactured today.
I do not think it was fair to say that the seller was selling counterfeit parts, but was probably supplied counterfeit parts that you could blame him for not testing each part. Very common for vintage parts to be counterfeit/ remarked.
Was there something about the MOS manufacturing process that caused so many chip failures, even as in this case a chip that doesn't have a heat problem?
For your other PET, have you installed the additional bypass capacitors along with the new RAM chips? They can be sensitive to VCC ringing due to improper bypassing. This is more of an issue with DRAM chips, tough.
Enjoyed watching it. As always. With the new intro even better. makes me think to also put intros to videos in my channel. Where did you only got the idea from? Awesome!
Maybe you should undervolt the RAM chips a bit to reduce power heat and power consumption. Say run them at somewhere between 4.5 to 4.9V. if the 5V is regulated with a 7805, replace it with an adjustable 317 regulator and turn the voltage down to the point the PET glitches/crashes then turn it back up slightly.
12:56 (caption) After all it's one of the strongest contenders to worst computer keyboard ever a(wk)ward. The first moment I saw one of these first-gen PETs I found that damn keyboard strikingly similar to that in an '80's cash register, keycap sticker colour coding included, and I still think of early PETs as "the cash register model".
It looks like he's holding a decapitated head when he's holding that PET monitor... In other news perhaps he could have also replaced that RAM chip that had missing pins.
I was wondering the same thing. edit: In another comment he answered that and I quoted it below. Adrian Black "I'll be making a hopefully cool video soon where we try out the broken chips in a good machine and look for the faults with the logic probe and oscilloscope. Hopefully to learn to detect those failures on other machines. "
