If they are missing their case screws, then that makes the machines highly suspect. It means people have been inside them before you, and essentially all bets are off. Anything could be going on, because you have no idea why someone else felt a need to go in there, or what they did while in there. It just means there are some assumptions that you can no longer make when trying to diagnose what might be wrong. You have to start kind of from scratch and eveything is suspect, from a simple bad batt or cap to fried chips or parts of chips.
On Tue, Nov 13, 2018 at 4:14 PM Britt Dodd <[email protected]> wrote: > Thanks Kurt --- the machine is absolutely non-responsive > (basic,enter,beep,enter does nothing), so I suspect removing the battery > might be a better first step, rather than immediately breaking the probe > out.... > > Does anybody have measurements on what the case screws dimensions are > (length, thread size, pitch)? All 3 of the 200s were missing case screws, > which I'd eventually like to remediate. > > On Tue, Nov 13, 2018 at 4:03 PM Kurt McCullum <[email protected]> wrote: > >> >> I ran my 200 without a NiCD for about a year. It worked fine. I did >> finally put a new NiCD into it this summer. I saw a similar error when I >> tried to put a super capacitor in place of the NiCD. But this gave me the >> horizontal line error. Removing it fixed my problem. I'm not sure if yours >> is the same but thought I'd mention it. >> >> Kurt >> >> On Tue, Nov 13, 2018, at 12:59 PM, Britt Dodd wrote: >> >> Good afternoon, >> >> Until this past weekend, I've never given serious thought about the >> TRS-80 project I have on my project list, but after attending the Tandy >> Assembly, I am now the proud owner of 1 Model 100, 3 Model 200 project >> machines and a CoCo 2! I'm trying to get the 200s up and running...they >> boot to a screen with lines, I've taken one of them apart, and cleaned up >> the ribbon connector with Deoxit, which didn't seem to help. It almost >> seems like the panel is "on" but not initializing properly, so I did the >> cold boot and the "arctic boot" procedures, to no avail. >> >> Something caught my eye on a VCF forum post, where someone had mentioned >> that if the NiCD battery isn't fully charged, the machine's RAM could be >> 'somewhat preserved' in an unconsistant state and recommended removal, and >> that the NiCD battery's presence was only intended to persist RAM contents >> long enough to change batteries. Is that true (NiCD battery isn't needed)? >> And as a follow-up, although capacitors "appear" okay, would a re-cap be >> needed for this? Traditionally (i'm a Macintosh/Amiga collector -- until >> now), recapping was mostly needed for SMD components, and through-hole >> passives typically are considered reliable, is this true here too? If NiCD >> battery isn't needed, I plan on snipping them from the 200s and the 100 I >> have too, since I could easily just offload (via serial) to a PC or >> something. >> >> >> >> Thank you, >> Britt >> >> >> -- bkw
