17 Dec
2009
17 Dec
'09
3:03 p.m.
On 17 Dec 2009 at 19:00, Tony Duell wrote:
That sounds mostly analoge (there are very few digital
ICs in circular
metal cans -- I said 'few' rather than none, because I am old enough
to remember at least one RTL series in such cans :-))( Possible the
head amplifiers, etc?
I recall that DTL (and early ECL) came in TO-100s. Somewhere, I've
still got a few Fairchild 8-bit addressable memories in TO-100. I
believe that the Motoroal HEP mWRTL kit came in TO-100 packages.
The second card is labeled "READ/WRITE AMPL. 30 IPS, 4TRK". The TO-
100's are MC1710G (differential voltage comparator). There are 4
uA709 op-amps on the thing.
The frontmost PCB is labeled "SERVO CONTROL, 30 IPS." and has 4 uA741
op amps on it, a couple of LM321H (TO-100) preamps, a couple of TO-3
darlingtons (MJ900, MJ1000) and an LM308 op-amp. But there are 6
trimpots, with no labeling other than "R9, R10, etc." which might be
a problem if adjustment were called for.
Comparing the interface connections with QIC-36 shows that it's not
QIC-36 (e.g. Drive select address lines connected to 74368 outputs,
etc.).
I thought the drive electronics looked a little to dumb to be a QIC-
36 interface.
Any other ideas?
Thanks,
Chuck