Buddy can you spare me an EPROM...

[Chris Crosskey]

Hi All, 
This is a bit of begging letter. Looking at the ROM's that I've got 
and am likely to get, I'm going to run out of 2716 and 2764 EPROM's 
pretty easily. I've got plenty of bigger EPROM's, 27C512's adn 
27C010's mostly, so I'm willing to swap for them, on a one-for-one 
basis. I've also got some PAL's PALCE's and Altera PLD's that I'll 
swap for. 
Also, it seems that the 8031 and 8051 NMOS microprocessors have been 
obsoleted (Juergen can you confirm, your address indicates a 
connection with Siemens and they used to make them), these are needed 
for the Elektor MCV. For some reason the 80C31 CMOS EPROM can't be 
used, but I think I know why. The original circuit uses a signal 
output on the uP as an AC line that it recifies and charge-pumps down 
to get a -3V line to provide the op-amp with the ability to swing to 
0V, the CMOS uP would not handle the current being demanded (tiny 
though it is). However the re-laid version I have has a facility for 
using a bipolar supply (the original was a single 12V supply), which 
might allow it to use the 80C31, and would also allow the use of a 
more powerful op-amp than the TL061 that it currently has to use.
I have a few 8031's, and might be able to get a few more, but I don't 
know how long the place that has got them will have them for. So it 
joins a list of things to keep an eye out for for the moment, and hang 
on to the ones you've got. 
	Talking of MCV's, has anyone got any details about the PAIA 
unit that's supposed to be out, like is out, and what does it cost. I 
emailed honcho a while ago, but, probably due to an act of AOL, never 
got a reply....
One last beg, can someone re-post the fix for using a 1K NTC tempco in 
Gene's circuit, I think it starts....
replace the 56K resistor with the tempco, replace the tempco with an 
18R resistor and change the feedback resistor to ....what ? I've 
re-re-layed my single VCO board to allow both sides of the divider 
chain to run over the top of the tranny pair. Tranny pairs now 
supported are the MAT-02, MAT-04, the LM394, the Elantec EP2016 (I 
think I've mistakenly referred to it as an EL2016 before), the 
SSM2210. Although a 3046 might work I wouldn't recommend it for 
substrate grounding reasons.
chrisc