Author Topic: My first tube receiver  (Read 1743 times)

Offline Sir Thrift-a-Lot

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My first tube receiver
« on: May 29, 2015, 02:48:39 PM »
I just grabbed this from the local thrift for $5. They said "tested and working", but that could have meant they plugged it in and it lit up. It could also mean they cooked the OPTs   Monacor STA-300X Made in Japan.   PP 6BM8   Probably about 10-12 watts a side, from what I've read.   Diode rectified.   Tubes on the tuner and phono boards.   One of those "magic-eye" tubes for tuning indication.   It's a pretty cool little unit.   Looks like it will be worth the substantial work I'll have to put into it.   Well. substantial for me, anyway.   Someone who knows what they are doing could probably bang it out in a day.

It's alive!

Since they plugged it in at the store anyway, I decided to try it.   It played well and sounded good.   However, see the last pic, I think one of the tubes was redplating.   I'm still kind of new to the world of tubes and haven't encountered this first hand before, though I have read about it.














Offline Mongojustpawn

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Re: My first tube receiver
« Reply #1 on: May 29, 2015, 06:45:00 PM »
Great find, but that tube looks really hot.
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Offline Sir Thrift-a-Lot

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Re: My first tube receiver
« Reply #2 on: May 29, 2015, 06:57:05 PM »
Yes, a complete recap is in order.

Offline Mongojustpawn

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Re: My first tube receiver
« Reply #3 on: May 29, 2015, 10:33:48 PM »
Sir T, before you get into recapping, you may want to pull the tubes, clean the tube pins and sockets, do a cleaning, deoxit of all controls, check all solder joints, board connections, anything, like resistors look like they've been getting hot, I did a quick search for a schematic, found listings for Monacor in SAMS, but didn't know the model number for your receiver. Good luck with it.
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Offline Sir Thrift-a-Lot

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Re: My first tube receiver
« Reply #4 on: May 30, 2015, 08:43:58 AM »
All of that needs to happen as well, but those gray caps are time bombs, especially in the power amp section.   It's not a matter of if they will fail, but of when.