spencer@eris.UUCP (03/05/87)
Well, my Amiga that made it through a major car wreck this summer finally
got sick. Not like it doesn't deserve a break, I carry it with me everywhere,
I open it up and swap disk drives when I need extra ones, I put a 68010
chip in and broke off the lid screw holes so the case won't go back together
again. But I love my Amiga, I really do. Now it is sick and I have to take
care of it. I guess it was the 3 days of displaying an astronomy program
for my company at the Commodore Show here that did it in. I now get Blue
and Red on the output video, but no Green (and I thought sick things turned
green). So I traced the signal back to where there actually was something
and it is on the other side of a transistor labeled Q2 on the board. There
is a big "G" there, bet that means green! The Transistor has:
C3504
E-5H
written on the flat side of it. I called Radio Shack and they were clueless,
and I called some electronics speciality shops in Berkeley and they needed
some other reference number. I tried to call Commodore the last 3 days
with no luck (it's like calling Sony or Amtrack, don't companies this large
ever try calling themselves and find out that the danm number is _Always_
busy, all day, and then suddenly you get through only to hear a recording
that says the business hours and hangs up, even though it's still during
those business hours!) So I put it out to the net. My dealer can swap
chips, but board level repair requires sending the mother board to Commodore,
for a stupid 34 cent transistor. Does anyone know the real number I need to
give my electronics dealer to get the transistor?
These news posting programs should have a little detector to tell when you
are posting something out of frustration and ask you to post later on.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Randy Spencer P.O. Box 4542 Berkeley CA 94704 (415)284-4740
I N F I N I T Y BBS: (415)283-5469
Now working for |||||||||||::::... . . BUD-LINX
But in no way |||||||||||||||::::.. .. .
Officially representing ||||||||||||:::::... .. ....ucbvax!mica!spencer
s o f t w a r e spencer%mica@berkeley.edu
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-frazier@cti.UUCP (Rick Frazier) (03/06/87)
In article <2684@jade.BERKELEY.EDU>, spencer@eris.BERKELEY.EDU (Randy Spencer) writes: > > Well, my Amiga that made it through a major car wreck this summer finally > got sick. Not like it doesn't deserve a break, I carry it with me everywhere, > green). So I traced the signal back to where there actually was something > and it is on the other side of a transistor labeled Q2 on the board. There > is a big "G" there, bet that means green! The Transistor has: > C3504 > E-5H > written on the flat side of it. I called Radio Shack and they were clueless, The schematic (which you should really have if you plan to do much mucking about inside the amiga, available for 20.00 as part of the "schematic and expansion specifications" package from cbm) shows Q2, the green driver transistor as a 2SC2926. It's an NPN transistor, fed thru resistors r53 thru r56 by a 74hc244 (u6a). Coming from this '244 also are signals that go to the mc1377, shich generates the composite signal. If you have no composite output, (or a strange signal there), you may have lost the '244, and not the transistor. The 4 bits for each of red and blue come from another '244 (u5a) so that's why you could lose the green and not the other two colors. Denise (the 8362) feeds both these '244s. --rick -- DISCLAIMER: The foregoing is the result of a brain frazzled by the effects of insufficient sleep and a noisy phone line, and in no way reflects the opinion of my employer, friends, or enemies. I'm not even sure I really wrote it. UUCP: {decwrl,pyramid}!sun!cti!frazier DDD: 408-734-8533
grr@cbmvax.cbm.UUCP (George Robbins) (03/06/87)
In article <2684@jade.BERKELEY.EDU> spencer@eris.BERKELEY.EDU () writes: > I now get Blue >and Red on the output video, but no Green (and I thought sick things turned >green). So I traced the signal back to where there actually was something >and it is on the other side of a transistor labeled Q2 on the board. There >is a big "G" there, bet that means green! The Transistor has: > C3504 > E-5H >written on the flat side of it. That's a 2sc3504 - Japanese markings usually omit the 2sc prefix. Unfortunatly, it's a moderately exotic part "high resolution video driver". I don't recall exactly what common Japanese parts make good substitutes, but a jelly-bean American 2N2222A or PN2222 make a reasonable substitute, *IF* you are careful to remember that American and Japanese plastic case transistors have different lead arrangements - ECB vs BCE (or is it the other way around...) -- George Robbins - now working for, uucp: {ihnp4|seismo|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@seismo.css.GOV Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
jimh@hpsadla.HP (Jim Horn) (03/07/87)
. . . . . 'Tis a 2SC2926. Check the ``Schematics and Expansion Specifications''. Jim Horn