Barn Find

[sodderboy]

Bath tub? Water? Suds? Power washer?
I may have had a plastic chassis go through some of this gauntlet, but I have kept water far from electronics. SL4K switch boards and such are cool with ultrasonic water-based cleaner, I detail front panels/controls with damp textiles, no more wet solder sponge, thats kinda it.
I stick to REACH compliant chem and compressed air.
Interested in the refurb!
Mike

 

[13engrsapper]

One of the things I've done with old questionable gear is do a quick bath in 99% Isopropyl Alcohol and heat gun to dry...use a toothbrush and any questionable parts dry quickly...

As far as getting my Nikko to run the units I have used the NEC 2SB600/2SD555 TO-3's which are like 15amp 200 watt transistors (6 each of them each) ...so that will explain the copious heat sinks...these things get REALLY hot...Nikko did not mess around with under powering anything...everything was pretty hefty wattage (at least the stuff I have)...so making sure those transistors are getting adequate heat transfer is kinda important especially after sitting for that long.

I need to revisit why I kept blowing transistors on the left channel, there are other obscure transistors used to control the voltage maybe 4 on each channel and very old zener diodes with specific call outs that were kinda hard to source...

Find a manual if you can...it will save you lots of trouble.

Just be careful with alcohol, some things plastic hate it, acrylic for example. There is no fixing acrylic exposed to alcohol.

 

[Disco Volante]

Judgment Day. Hooked it up to a couple of old low-efficiency Sony speakers and my somewhat makeshift Variac (still need to build a neat box for that). At first just a deadly quiet. Mains fuse blown. Then at about 150V the relay clicked and I removed the variac after making sure nothing was smoking.
After the speaker relay clicked the LED meters started moving, but no sound. A quick troubleshooting revealed a very strange wiring of the speaker terminals (A and B are in opposite phase, but only on European models), and some oxidized contacts both in input sockets and the strangely flimsy speaker connectors. The combo kind with screw and banana. I guess the banana option has never been used.
With all the dodgy connections squared away: ALAS, sound!

 

[Disco Volante]

As expected, this amp has muscle. Excellent control of the lower octaves.
Still a few things to sort out: some 100Hz hum, even with shorted input, and a good amount of hiss (about the same level as my Quad 303).
I would expect a good amp to be very quiet, so a bit of measuring and sorting, but it's fun that it makes music after all these years of idle storage under less than ideal conditions.

Cheers!
V

 

[Disco Volante]

This beast was sitting next to the Nikko. Technics SA-700
The "Boss Hoss" of 70's recievers, the fascia was painted black and it's equally cruddy inside.
Tempted to rebox the power section in some nice heavy steel. On the other hand, SA-700s fetch good money on Evilbay...