Voltages too high [resolved]

[Baobei]

Hi all,

I just finished building the basic Crack, but my voltages are way too high. (Please see below)

The incoming AC voltage measured 244V (UK), so I wired the transformer accordingly. The transformer voltage tests were fine.
Resistance checks were good as well. Everything glows as it should (as far as I can tell).

I followed the instructions from the other thread with almost the same problem (https://bottlehead.com/smf/index.php?topic=11312.0) and reflowed the joints of the black cables. No change to the measurements. I'm hesitant to plug it in again, as the V is well beyond the rating of the caps...

Voltages measured:
1. 182V
2. 388V
3. 0V
4. 389V
5. 182V

6. 0V
7. 243V
8. 0V
9. 243V
10. 0V

Picture of my wiring in the attachment.

Thanks!
Simon

[Paul Birkeland]

Just like the other poster, you have a black wire that's not properly connected.  The high resistance of this connection is giving you those wacky voltages.   

Do you happen to have a clip lead?

[Baobei]

Thanks for the quick response!

Yes, I do have a couple of clip leads.

[Paul Birkeland]

clip one to terminal 21 and the read lead of your multimeter.  Do this with the amp off and wait for the power supply to bleed down.

Once that is done, power the amp back up and touch your black meter lead to:
Terminal 20
Terminal 14
Terminal 12
Headphone jack outer lugs (all connected together)
Terminal 3

Let us know what voltages you see for each of those connections. 

-PB

[Baobei]

They all measured the same:

20: 492
14: 492
12: 492
Headphone jack outer lugs: 492
3: 492

[Paul Birkeland]

You do have the tubes in for these measurements, correct?

[Baobei]

Yes, they are in. I noticed a faint hissing sound from the 6080.

[Paul Birkeland]

I would go back and physically pull on each end of each black wire with your needle-nose pliers to find the loose one. 

[Baobei]

Okay, I finally had some time to look over everything again. All wires properly soldered. Just in case I resoldered some joints, removed some solder where it seemed excessive. No change whatsoever. I started to question my sanity.

UNTIL............

I looked at my meter and realised that it was in the wrong setting (AC)! 

Well, problem solved. All V are easily within 10%. It must have been running perfectly from the beginning.
Not much lost, except some of my pride (well deserved I may add).

Thanks PB for the very quick responses and patience!