4 Sep
2014
4 Sep
'14
6:42 p.m.
On Mon, 1 Sep 2014, drlegendre . wrote:
Being pretty new to all this, I can tell you that
reading datasheets and
devising tests for 74XX series ICs is a very good way to learn your way
around the world of digital logic - it's actually been a very helpful
series of learning exercises.. far better than listening to a lecture or
reading a textbook. Man am I glad I picked up & repaired that proto /
trainer chassis.. dang thing has really been coming in handy!
Do you have any idea who made/sold it? It's pretty similar in concept to
a Heathkit ET-3200, but way more versatile. Based on the workmanship
(the occasional lack of..) I think it was built by a student, probably
as part of a tech school course, or maybe a mail correspondence course?
Either way, it's a decent piece of equipment and it works great after
going through it -
https://nerp.net/~legendre/altair/photos/proto-trainer.jpg
I don't know which model you have, but that trainer was made by RSR
Electronics. Do you have any photos of the boards inside the trainer?
I have a similar but slight newer RSR Electronics trainer in my active
repair pile right now. As you suspected, these were commonly sold as kits
and were often poorly assembled. The one I have will need to be completely
resoldered, and all the toggle switches will be replaced (the assembler
melted them when soldering and several don't work at all). It also has
failed/popped filter caps in its DC power supply and a cooked pc board
(melted black goo) where the TO-220 transistor is mounted to the board
that the rotary switches are also soldered to. I found an inexpensive
Aavid TO-220 heatsink that fits the board layout and silkscreen perfectly
that I plan to install. One major gripe I have with the design is a lack
of a Molex connector for the power transformer which made removing the
main board extremely difficult (I finally snipped the wires off at the
board). The board was clearly designed for a header, but like the TO-220
heatsink, they were being cheap and left that out of the kit. I've already
sourced a header/connector though and will be fixing that when I redo the
rest of it. If you decide to replace the electrolytics in one of these, be
aware of the lone bipolar/non-polarized cap used in the function generator
circuit. If your boards are the same as those in the trainer I have here,
I have a repair parts list that also includes all of the electrolytics.
