Quote:
Originally Posted by SiriusHardware
I'm guessing that if you can take a shot of the underside of the PCB, we'd probably like that one in the same super hi-res as top view.
As Owen said, if you can positively identify the +5V and 0V supply rails you can probably power it up to the extent that it will produce a UHF RF signal which can be tuned in on an analogue TV. That's assuming that you don't have the actual power supply for it of course.
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Quote:
Originally Posted by onewatt
I'm visiting site on Monday to collect books and paperwork from a lifetimes interest in electronics. I'll probably have to filter afterwards and it may take me until next weekend, but I'll see what I can find on softy2.
Some more pics which hopefully work for all.
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Back to the original post - On what turned out to be a Softy-2:
I've been having a look over the PCB Photos, and found a few things.
1. The DC Power input DIN-Socket is actually 3-pin (even though it looks like a 5-pin one), as there's actually only 3 pins on underside of the PCB (Front 2 are shield ground). If you look carefully, it appears there's only 3 contacts in the holes (unless they used a 5pin one and cut the PCB-pins 4&5 off).
To ensure the correct pin numbers are referred to, I looked for a 5-pin etc. DIN socket picture on the 'net, with the Correct-view ones on it - which was surprisingly difficult to find (Wikipedia etc. doesn't show any numbers, and many are actually the mirrored opposite-view into mating-pins end of plug even though they say it's the socket). But this one does seem right:
https://connector.pinouts.ru/5_pin_DIN_female/
2.
The middle of the '5' (actually 3?) contacts (Pin 2) is Ground (0V)
3.
Pin 1 (The
top-right, when looking into socket, with board the correct way-up) goes into the emitter of TR5, whose collector (& Tab) goes to IC13 (7445) Pin16 (Vcc=+5V). So this must be a PNP transistor, and appears to be used in conjunction with TR1/2/3/4 & DZ2(4V3?) to form a (Low-dropout) +5V regulator. So I would guess that
voltage on the connector Pin1 would be around +6V - Trying +5.5V to start with and monitoring voltage on the +5V rail should be fairly-safe. Or
alternatively, just connecting +5.0V directly to TR5 tab etc. should also be OK.
4.
Pin 3 (The
top-left, when looking into socket, with board the correct way-up) goes into the input of a 100mA voltage regulat (VR1), whose 'Gnd / Adj' centre-pin goes to cathode of DZ3(20V?) with DZ4 anode to ground. I'm not sure what this regulator type is, as I the photos don't show the right view, but if it was a standard 78L05 this would give +25V output for use as the Vpp programming voltage. So I would guess that
voltage on the connector Pin3 would be around +28 to +30V (But should
only be required for actually programming EPROM's with it).
So hopefully it should be possible to power it up, even if the original PSU can't be located.