Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: rafe on October 09, 2023, 03:26:04 pm
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Just received the choke,reverb,power and output transformers from a 67 super they are all from 66 except the reverb it's -7-01.....I bought them knowing(being told) the output trans was blown. I tested it with an ohm meter everything was fine no shorts and 1/2 the ohms across the center tap ran 5v volts through it and it looked good .....I hope the power transformer is ok. I checked with the seller and He said He was 100% sure the tech told Him it was the output tranny .....but that was in 04. Either way an 18th week of 66 super output tranny is worth what I paid for them all. Thanks in advance for any thoughts on this ......
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I am trying to sort out the wires on the power transformer this is where I am at ...or as good as i have gotten... 2 Yellows 5v to gz34...2 Greens 6.3v y/g CT to heaters and pilot .....2 Reds 360vac y/r CT to gz34....yellow/blue grid bias on gl6's.....two blacks are 120vac. My only question is because i am basing this on a hammond transformer spec sheet is; The 2 green wires are the the thickest gauge wires am I correct in my deduction? Nevermind it's on the layout , I'm good
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Power transformer has passed the continuity, short and smell test I am going to throw some voltage through it later. I am thinking 5v's , but I am going to go through a few videos first to see what I am looking for and how I should do it .....
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It may be fine with 5v. But if the varnish on the wire is degraded you may need more than 5v to see it act up. I am not sure what a better diagnostic would be. But I wouldn’t run with that diagnosis until another method to verify. Just my .02
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"Just my .02"
,I appreciated the advice , I will do a lot of research , just figured it is a good starting point, I will post the various numbers after I test it, bringing up the voltages in stages. I wish I had more of a back story on this, amp these (I believe) were all pulled out 20 years ago if and how they were tested I don't know. I had to strip the wire ends on the PT and OT to test them, so there are questions like what happened to the amp and why it was gutted! if the (??tech??) thought the OT was bad in '04. I may try to get more of a back story ..............
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A-OK R2R 755, R2RY 378.2 & 378.4. R2RB 323.3 & 331.5. Y2Y 5.5. G2G 6.98 G2G/Y 3.5 & 3.5 all tested at 120 volts So I see no problem at all here ....so far so good .......next tests will be for the choke and reverb ....I'm not sure how to test them ....more research it's not as easy to find but it's likely out there OR in here! Thanks in advance for any pointers!
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Choke is 94.1 ohms reverb 2k on one side 1 ohm on other ....no shorts....I believe these two are good, unless someone knows the numbers are off for some reason , I found out nothing online about testing them ....I see how to make a choke though....Thanks R