kaimaiguy wrote:None of this is terribly reassuring as you see I am the obviously unlucky fool who won Ian's cyber corpse on Trademe which you speak of here.
Yep.. Ian's just emailed me, suggesting you may have been disheartened by this thread. I should point out Rick, that around 50% of the machines acquired by the denizens of this board are in this state and need lots of love and attention... and nearly all of them come back to life. Tezza's IIgs was one exception, but there's no fixing motherboard corrosion from battery acid.
kaimaiguy wrote:Ian described it as a working model with no CRT display but after reading your posts I have suddenly lost any enthusiasm for the much anticipated project At very best it will be a challenge far beyond my knowledge and abilities. Just getting started out with the ole timers but was hoping my first project wouldn't be a pre designated disappointment.
Rick, My comments are meant to let the others here know that the machine may need a careful disassembly, clean and check for corrosion. (and if you have the resources an alcohol bath and a little strategic oven drying for some boards)
There are plenty of people on this forum and on the international forums who are talented enough to point you in the right direction. I doubt the machine is "dead" (at least not permanently) although I would have advised something a little less "off the beaten track" (more available parts, i.e. C64, Apple IIe, ZX-Spectrum etc) as my first foray into restoration. Maybe a second slightly easier project in parallel to keep your enthusiasm up?
kaimaiguy wrote:I would imagine that if the CRT itself is actually burned out finding a replacement will be like trying to find a wallet that fell from a Cessna Skylane stuffed with $3- bills. OR be fair trade for the punjab diamond.
I wouldn't necessarily assume that yet Rick. CRT's
can blow, but there's plenty of other more likely candidates. You're more likely to have to replace a few capacitors controlling the screen.
The main thing is going to be to very carefully disassemble and clean, especially around the HT sections of it. Buy lots of isopropyl and WD-40 contact cleaner and q-tips and find a well ventilated area and get busy. Re-seat (and clean) any socketed chips. Go over the circuit boards and look for dry/loose solder joints... and THEN we start looking for dead components.
if the CRT or the HT Transformer is blown, and you try looking for a "screen for an HP85B", also remember that HP probably made neither of these items, and it's a matter of hunting for the component by it's real name. (for example it might be a "General Electric 12345A")
[UPDATE] - It looks like
your prayers have been answered Rick, if you can get the machine diagnosed reasonably quickly. New Screen. Main board. etc.
kaimaiguy wrote:Actually expecting it's arrival via Post tomorrow. I'll send you all a vial filled with the ole git's teardrops as a made in New Zealand keepsake.
Best of luck.... and one more thing.
Get a schematic, and be VERY VERY VERY CAREFUL around the high voltage sections of the screen. These voltages are still present with the machine switched off and unplugged.