Reduction resistance and voltage question

[Yvanyvan]

Hi,

Thanks for the previous help, finally completed my built and came to resistance and voltage check.

3 questions:
1. All resistance is good except 31 - I get there -1.6M instead of 0L. Where can be the problem?
2. When it comes to voltage testing - nothing turns on, but fuse is fine. I get proper readings on transformer terminals. Where do you suggest to start checking?
3. I have purchased manual for the friends unfinished kit for 120vac. Would the voltage readings differ from specified in manual with 220vac transformer I replaced, or can I refer to manual?

Thanks!

 

[fullheadofnothing]

1. This is probably fine. That is a very large resistance.

2. Did you do the power transformer testing before building the amp, as specified on page 21? Were all of those results correct? You say "nothing turns on", but did you do voltage readings? What were they?

3. The difference between the types of transformer on on the primary side, secondary voltages will be correct as long as the correct transformer is used with the correct incoming voltage. If you used the wrong transformer, the tests on page 21 would have shown the wrong voltages.

 

[Yvanyvan]

1. This is probably fine. That is a very large resistance.

2. Did you do the power transformer testing before building the amp, as specified on page 21? Were all of those results correct? You say "nothing turns on", but did you do voltage readings? What were they?

3. The difference between the types of transformer on on the primary side, secondary voltages will be correct as long as the correct transformer is used with the correct incoming voltage. If you used the wrong transformer, the tests on page 21 would have shown the wrong voltages.

Voltage reading were fine - 220, ~130, 9. I will do more checks with routing and post the results here if nothing helps

 

[Yvanyvan]

3. The difference between the types of transformer on on the primary side, secondary voltages will be correct as long as the correct transformer is used with the correct incoming voltage. If you used the wrong transformer, the tests on page 21 would have shown the wrong voltages.

Transformer is not original, but supplies right voltage. I think i may have got the polarity wrong, how can i test it? I have wired as shown in the pic.

 

[Doc B]

If you are not using the power transformer that we supply in the kit it is not possible for us to answer any questions about how it should be hooked up with any certainty. We simply don't know enough about it.

Nothing turns on but you get voltages at the transformer terminals - that would indicate that at least the transformer is getting power when the preamp is switched on. Go through the voltage tests on the circuit and give us any voltage measurements that are not correct.

 

[Paul Birkeland]

The power transformer supplied with the Reduction is without equal.  It would be a very, very good idea to get a replacement from us, as there are very few winders out there who could create a replacement with adequate performance.

-PB

 

[Doc B]

It would be most helpful if you could provide us with a photo of the entire underside of the preamp.

 

[Yvanyvan]

Ok, i did some homework and found stupid mistake with all 22Ohm resistors.
Replacement made reduction work, but only with the left channel.

I still get 0V from 33, while 37 gives good 5.9
Both 38 and 42 give 10V

The voltages on the right channel are:
2. NOT OK: 148 instead of 70-90V
4. OK: 150 / 145-155V
7. NOT OK: 149 / 70-90V

The checks i did:
-I did not manage to find wiring mistakes
-I have resoldered 33
-I have checked 5340 diode. it was ok
-I have swapped tubes

 

[Doc B]

Photo?

 

[Yvanyvan]

Photo?

 

[Doc B]

Aside from the Dayton caps no other part looks quite like the ones we supply in the kit - different wire, different terminal strips, different jacks, different ground post, etc. That makes it a little more difficult for us to spot what might be different than a stock build, particularly when the image is so dark. Can you give us a photo of the whole chassis, perhaps a little bit brighter?