CIHFA1 amp replace output transformer

[jukeboxmarty]

What type of tubes are in the 6973 slots? Are they genuine 6973's? Some tube resellers substituted other tubes and re-marked them as 6973's.

In a true 6973 pins 1 and 8 are bridged internally as well as pins 3 and 6.

[prime]

I have originals in there and have tried many from working jukeboxes, the strange thing is, when i check pins 1and 8 from the bottom, no tube no continuity, with tube installed continuity is there. Both tube 1 and 2 tube sockets read exactly the same, when i add power to the tubes on both tubes feed is on pin 9 and 8 9 is plate 8 is screen but for some reason power not getting from 8 to 1 on tube 1. I was thinking it must be a lead going to the tube that is affecting the power transfer from 1to 8 also on tube 1 there is o vlts at pin 7   on tube 2 pin 7 -37vlt   pete

[jukeboxmarty]

If the tubes are correct and undamaged, your only other choice is a bad tube socket.

[jukenorman]

As has been said many times on this forum, checking continuity with a digital meter is fraught with issues!

Norman.

[prime]

I also have an analog, what am i expecting to see to confirm continuity Pet

[jukeboxmarty]

Also, it makes no sense to have any voltage at pin 7 on either tube. Both pin 7's are tied together and should be at ground potential.

[prime]

I definitely get -37 on tube 2 at pin 7 0 on pin 7 tube 1, so im not sure why nothing has been touched at tube sockets all factory parts, and continuity is still confirmed with analog, i set it at x10k and it read zero at pin 1 and 8 on both sockest with tubes installed. pete  This may confirm issue with socket? photo f connections....

[jukeboxmarty]

I'm not disputing the results you are seeing. But according to the schematic both pin 7's are tied together under the chassis. If everything is wired correctly having different voltages on each pin is impossible (unless my schematic is wrong).

I know it's probably frustrating!

EDIT: your photo confirmed that both pin 7's are tired together under the chassis... Not sure have they can yield different voltages.

[prime]

In the photo if you look the lower socket you will see there is a jumper wire from pin 7 to pin 2 and that connects to tube 12ax7 should that connector not be there???

[jukeboxmarty]

Pin 2 is unused on the 6973. They are just using it as a tie point. In this case it's a ground pin.

[prime]

When i follow the connector from pin 2 to the 12ax7 tube it connects to the 390k resistor 149 on schematics it shows voltage .....

[jukeboxmarty]

Something seems to be going here on that doesn't meet the eye.

I know it's a daunting task, but you are the only one that can compare your amp to the schematic.

Please don't take this wrong, but we can only help when the information provided makes sense.

The reality is when two terminals are tied together with a jumper wire such as your pin 7's, they cannot yield a different voltage. Maybe there is a connection or solder issue? I don't know???

Based on the info provided... I can't provide further suggestions.

[jukenorman]

Might your meter be faulty?

Norman.

[prime]

I have used two meters with same result. I agree if power at one tube with connector there should be power at both. Not sure how I lose power between pin 1and8. But more important is you stating I should have no voltage at 7.

[prime]

Ive re soldered all connections to both tube sockets, I will try in the morning to power up and redo voltages. I do have two meters one fluke auto range and an analog so testing will be twice. I tried the amp again on my bench and have good contact all points, if the voltages do not make sense between the tubes i can only imagine it is a defect in the one socket that separate's when the tubes heat up. pete ps any thoughts why it takes 20 to 30 seconds for sound after needle lands?