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Joe
Posted on Wednesday, March 30, 2011 - 01:58 pm:   

I'm trying to rewire a hi-off-lo switch that was bypassed anybody have any pics of that switch from the inside of a 212HD130?
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Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Thursday, March 31, 2011 - 11:05 am:   

Here-I'll try to get these to post. They might be too big

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Joe
Posted on Thursday, March 31, 2011 - 02:25 pm:   

Thanks Mike , You rule!!!!
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Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Friday, April 01, 2011 - 09:34 am:   

By the way, don't mind the sawdust. It's been down in the shop and it's a chassis I keep around because I've been too damned lazy to fix it! Mike.
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Joe
Posted on Saturday, April 02, 2011 - 07:20 am:   

Hey Everyone , I' m going to test all the caps everywhere. I want to put new tubes in , anyone no what type and how I test the tube sockets before I put he tubes in ? The caps date back to 74 and the serial # is 000575 .Can anyone Date it . Work in progress!!!!
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Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Saturday, April 02, 2011 - 12:58 pm:   

I've got and old one that has sn in the 800's, I believe but dating any closer than the range of mid to late 70's is hard. I would assume 76-77 would be close. The sockets, you don't really test. You clean, re-tension and go. THose are actually pretty good sockets to begin with. I like to clean, re-tension and then install the new tubes, then bias. REMEMBER to discharge the caps before touching.
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Joe
Posted on Saturday, April 02, 2011 - 07:16 pm:   

there were 6L6's in there before the first tube in wrong there was no keyway when I pulled it out, blew 2 3.9 ohm 1w resistors on the driver board , they are on order , are these the corrct tubes? and whats the difference between the 6L6's and El-34's ?
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Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Sunday, April 03, 2011 - 04:55 am:   

Does your amp have a 12ax7 in the little tube socket?
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Joe
Posted on Sunday, April 03, 2011 - 05:50 am:   

No , just four main sockets .
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Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Monday, April 04, 2011 - 08:03 am:   

That's the later version, let's say 77-79. just guessing. That has a little different bias structure. Go to adjustments title and the first item covered by Steve is the bias procedure foir yur amp. It the one that say something to do with driver board db2 or something like that. It will detail how to bias your amp correctly. Mike.
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Joe
Posted on Tuesday, April 05, 2011 - 01:03 pm:   

Anyone know what tubes go in my 212hd130 it does not have a 12ax7 ? also should the tubes be in when biasing ?
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Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Wednesday, May 11, 2011 - 04:32 pm:   

I'm sorry I never noticed this post-old age I guess. If you have a 77-79 2-12 and it has the silver badges with the black lettering, it SHOULD have 6ca7's or EL34's in it. Bias with the tubes in.
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Bob Ressler (pezbob)
Username: pezbob

Registered: 06-2011
Posted on Thursday, June 02, 2011 - 11:25 am:   

why would that be bypassed? mine is like that too
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Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Thursday, June 02, 2011 - 02:35 pm:   

Could be that one side of the switch was bad. Just a thought.

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