Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: andyh on January 13, 2021, 12:20:52 AM

Title: Failed voltage check. [tentatively resolved]
Post by: andyh on January 13, 2021, 12:20:52 AM

I think I must have missed something but can't see it. Voltage check

1 -0.7
2 -0.7
3 0
4 -0.7
5 -0.7

6 0
7 0
8 0
9 0
10 0
 
I,ve gone all the way through the manual following the wiring instructions and can see nothing wrong/incorrect. :'(

Title: Re: Failed voltage check.
Post by: Deluk on January 13, 2021, 02:47:36 AM

First thing I'd do is check the fuse......................

Title: Re: Failed voltage check.
Post by: andyh on January 13, 2021, 02:49:13 AM

Tubes are glowing so assuming it's ok. (Checked, fuse is ok)

Title: Re: Failed voltage check.
Post by: Deke609 on January 13, 2021, 03:27:03 AM

Make sure that (1) you've got the test leads plugged into the correct jacks on the meter; and (2) you've got the meter set to measure DC volts not AC volts.

cheers, Derek

Title: Re: Failed voltage check.
Post by: andyh on January 13, 2021, 03:40:07 AM

Yes checked, also checked with a second meter just in case.

Title: Re: Failed voltage check.
Post by: Paul Birkeland on January 13, 2021, 04:01:06 AM

I see a diode lead at 19L that's poking out and maybe touching another lead, which will short out your HV supply (and should blow the fuse).

Can you perform the power transformer voltage test that's in the manual and let us know what you get on the high voltage winding? (The one that should be about 160V)

Title: Re: Failed voltage check.
Post by: andyh on January 13, 2021, 04:15:06 AM

Hi Paul,

Black lead to term' 11 red to 12 on transformer, it's reading 175v.

Title: Re: Failed voltage check.
Post by: Paul Birkeland on January 13, 2021, 04:23:41 AM

How about the DC voltage between terminal 20 and 21?

Title: Re: Failed voltage check.
Post by: andyh on January 13, 2021, 04:26:16 AM

235v

Title: Re: Failed voltage check.
Post by: andyh on January 14, 2021, 08:12:07 AM

Any ideas anyone??

Title: Re: Failed voltage check.
Post by: Paul Birkeland on January 14, 2021, 08:16:57 AM

How about the DC voltage between terminal 3 and terminal 20?

Title: Re: Failed voltage check.
Post by: andyh on January 14, 2021, 09:20:48 AM

3-20 = 0v

out of curiosity I measured 3-19 =90.7v

Title: Re: Failed voltage check.
Post by: Paul Birkeland on January 14, 2021, 10:24:04 AM

How about the DC voltage between terminal 3 and terminal 15?

and the DC voltage between terminal 3 and terminal 13?

Title: Re: Failed voltage check.
Post by: andyh on January 14, 2021, 10:33:03 AM

3-15 = 196v
3-13 = 172v

Title: Re: Failed voltage check.
Post by: Paul Birkeland on January 14, 2021, 10:35:37 AM

Voltages between 3 and B2?

3 and B5?

Title: Re: Failed voltage check.
Post by: andyh on January 14, 2021, 10:42:26 AM

Both 173v

Title: Re: Failed voltage check.
Post by: Paul Birkeland on January 14, 2021, 10:53:14 AM

OK, now measure the DC voltages between 3 and 2, as well as 4 and 2.

Title: Re: Failed voltage check.
Post by: andyh on January 14, 2021, 10:56:54 AM

I did move the capacitor near 20/21,  and poked around with the diodes there as you was showing an interest in that area.

So out of curiosity as there is power there I've redone voltage check.

Results are

1 = 94.7v
2 = 172.9v
3 = 0.4v
4 = 173.6v
5 = 90.2

6 = 0.4
7 = 113.2v
8 = 0.7v
9 = 115.5v
10 = 0.4v

Title: Re: Failed voltage check.
Post by: Paul Birkeland on January 14, 2021, 10:58:54 AM

You may just have a loose connection or two.  Those are working voltages, out of curiosity, can you carefully measure the voltages at A3 and A8?

Title: Re: Failed voltage check.
Post by: andyh on January 14, 2021, 10:59:59 AM

Both 174v

Title: Re: Failed voltage check.
Post by: Paul Birkeland on January 14, 2021, 11:01:01 AM

No, A3 and A8 wouldn't be 174V.  That is pin 3 and pin 8 on the 9 pin socket.  No pins on the 9 pin socket should read that high (although 1 and 6 will for about ten seconds when you first turn the amp on).

Title: Re: Failed voltage check.
Post by: andyh on January 14, 2021, 11:02:28 AM

Sorry crossed wires excuse the pun,, is that 12u to a3, a8?

Title: Re: Failed voltage check.
Post by: andyh on January 14, 2021, 11:09:12 AM

2-3 = 174v
2-4 = 0v

Title: Re: Failed voltage check.
Post by: andyh on January 14, 2021, 11:15:41 AM

I think you meant 3 - a3       3 - a8  are both 1.5v

Title: Re: Failed voltage check.
Post by: Paul Birkeland on January 14, 2021, 11:17:13 AM

Yes, 3 is a ground.  It looks like your amp is working properly now.  I would poke around with a wooden chopstick and a cheap pair of headphones plugged into the amp to be sure nothing causes a popping noise when you poke around in there.  If you have a loose connection and you poke it, you will get a pop through your headphones and that can help refocus your efforts.

Title: Re: Failed voltage check.
Post by: andyh on January 14, 2021, 11:18:47 AM

Thank you so much for your help I really appreciate it.