32s won't power on



#11

I've just acquired a 32s that looks to be in great condition, with the small problem that it won't turn on. The keyboard seems to be in good shape, and I tried the standard first approach of pressing on the bezel beneath the screen. I opened it up to check the circuit board, and there aren't any cracks, which isn't surprising, given the unit doesn't bear any nasty dents or other signs of abuse.

The strange thing is when I put in the batteries, the LCD appears to receive power continuously, as there's the faint "glow" of the pixels which can be seen in an LCD that is powered, but blank.

Are these symptoms indicative of any common ailments in a Pioneer?


#12

I had a 17bii with the same problem. The best I could determine was the CPU was not seeing the XTAL clock, and was not properly executing the boot-loader.

I've also seen the contrast set all the way down so the screen only appeared to be broken. For the pioneers with a BEEP function, you can test this by resetting and pressing [0] [/] to see if the screen is broken but not the CPU. For the others, it requires measuring the current.

I do hope you get it working.


#13

Hmm, I don't see anything resembling a crystal on this 32s board. Odd. The only component besides the CPU is a fairly substantial beige item marked "226 10K". A resistor of some sort? It measures a lot higher than 10K Ohms - more like 16 Mega Ohms. Though if I reverse the polarity on the meter, it reads about 30 Mega Ohms.

Maybe I'll try to dig up a small magnifying lens and examine the wiring to the CPU.

#14

You might try this:
http://www.fixthatcalc.com/try.php

Or, perhaps, the contrast is set so low that you cannot see it? To adjust that, hold on key and press + or - to try to adjust the contrast.

#15

I have a 17 BII I bought on eBay as working that showed the same symptoms. I also disassembled it and nearly gave up on it. It turned out that a stuck key was the cause. I smacked it against my flat palm, and it's been flawless ever since.


#16

You know what, the 1 key DOES feel like it has no spring to it, and may be stuck... Hmm... I'll give this a try later when I'm home from work.

#17

Yup! It's definitely a stuck key problem! I undid the three metal twist connectors that hold the board against the keyboard ribbon cable as a quick way to disconnect all the keys with a little prying force, and I saw a bunch of 1s on the screen (along with a lot of weird flickering, since I was also loosening the lower zebra stripes on the LCD).

Now, the followup question: how to unstick a key on a Pioneer? I'll try the palm slap a few times, but assuming that doesn't work, should I attempt to drill the metal backing with a very thin bit and push the key outward with a toothpick? I don't fancy taking my chances with the 50 or so heat stakes that hold the keyboard in place.

#18

Well, good news, it's working beautifully now. I used up all the least invasive options for popping the stuck key, so I had to suck it up and pop the heat stakes. Fortunately the design of the Pioneers is such that the heat stakes aren't responsible for the pressure fit against the keyboard ribbon cable and LCD connectors (unlike the 28S, which is practically ruined as soon as you open it).

Somehow, the plastic dome under the 1 key was staying down when pressed, and not springing back up, though it could be pushed back up manually. I was about five minutes away from transplanting the keyboard mechanism from a 10B, when I figured I'd try experimenting a bit. I took my pocket knife, and made a tiny vertical incision radially at the lower edge of the plastic dome. It was just enough to reduce the tension holding the dome in its depressed state, and now it pops back up on its own like it should! The 1 key is a bit softer than the rest of the keyboard now, and makes a faint popping sound when pressed, but it actuates perfectly, with no bounce, and no hesitation. And best of all, no sticking.

To put the whole mess back together, since the heat stakes weren't available to provide rigidity to the keyboard anymore, I packed the case with a few rows of weather stripping to hold the keyboard plate against the front of the case. It's doing an admirable job of holding the keyboard in place, though I don't doubt there's a better way to do it.

So there you have it, another 32S rescued. And I almost found a use for my 10B, too. ;)


#19

Congratulations! And thanks for the interesting description of your repair.

I'm glad I could solve my keyboard-problem without taking the keyboard apart. For me, it was hard enough to open the case without causing too much damage :-).


#20

Yeah, the case was rather tough to open, but not nearly as difficult as a 48, and certainly not as destructive as a 28. The keyboard plate wasn't very hard to remove either, just time consuming, what with all the heat stakes.

Maybe if I can score another similarly damaged unit, I'll attempt some photos of the repair process. Might be a nice way to get a super cheap 42S...


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