uk crack builder, voltage issues

[tweedgv]

Hi guys

Ive recently received my crack (yesterday), painted the chassis (yesterday), and then spent the day building it (today).

resistance all check out great, but when i came to the voltage, every terminal is measuring more than it should, way more, like double.  every terminal that should read 0 reads 0, but every other terminal is up. is there a discrepancy with uk voltages? 

i've gone through the build and i cannot find a miss placed wire or such, but it is late....

thanks, any help would be great.

Gav

[Doc B.]

Does the power transformer say PT-3 or PT-3 240V, and/or does pin 2 say 120V or 240V? You may have received a 120V transformer in error. We can help you to figure that out and, if so, send a replacement.

[tweedgv]

tranformer says 240v bottlehaed pt3

[Doc B.]

Ok, let's eliminate the possibility of our having sent you a mislabeled transformer. Make sure the amp is unplugged from the wall. You will want to measure the resistance from pin 1 to pin 2 on the power transformer. It should measure about 47 ohms. If it measures around 12 ohms instead, we have sent a mislabeled transformer and we will need to send you a replacement.

[tweedgv]

yeah, thats fine, coming in at 48

[tweedgv]

if this would help, here are my readings:

1- 176
2- 381
3-0
4- 381
5- 170

6 - 0
7 - 232
8 - 0
9 - 230
10 - 0

11 - 0
12 - 0
13 - 380
14 - 428

20 - 0
21 - 475

a1 - 173
a2 through to a5 = 0s
a6 - 174
a7 through to a8 = 0s

B1 - 174
B2 - 380
B3 - 233
B4 - 174
B5 - 381
B6 - 232
B7 - 6
B8 - 0

[Doc B.]

OK, the power trans is fine. It looks like the voltages are high because the tubes are not drawing any current. Do the tubes have a faint orange glow inside?

[mcandmar]

I have a theory, did you wire the two 150v windings in series?

[Paul Birkeland]

Can you do a quick AC voltage measurement on terminals 4 and 5 on the power transformer?  That should give you about 6V AC with the tubes in.

I would really have to scratch my head as to why your voltages are so high if you didn't accidentally get a 120V transformer.

-PB

[tweedgv]

ok guys....... sorry i'm late replying, had to go to bed.

yes the tube is glowing.

the reading off the power terminal:

4 = 0
5 = 6

[tweedgv]

sorry mcandmar.  you've lost me.

thanks for the help though guys.

i did the last test on the TRS jack and both the tip and the ring behaved as expected....... climbed to 10 and 11 respectively before quickly reducing to 0.


i'm hoping its something stupid that i've done, and it probably is, this is my first ever project of this kind and to be honest.......

i'm babbling now......... stupid time difference ........ what time do you guys wake up anyway? haha

i'll do another wiring check.
 

[Doc B.]

Can you post an image of the wiring around the power transformer? My hunch is either the meter is giving incorrect readings or there is some issue with the transformer wiring. Also, could you set your meter to AC Volts and very carefully measure the AC voltage across pins 6 and 7 (black lead to 6, red lead to 7) of the power transformer and then measure the AC voltage across pins 9 and 10 of the power transformer? You should be seeing somewhere around 150 to 165 Volts AC. Possibly a bit higher. Set your meter to the 500VAC range or higher to be safe.

[tweedgv]

OK......

both 6 & 7 and 9 & 10 are indeed giving me 167.

[tweedgv]

couple more pics

[Doc B.]

OK, set your meter back to DC volts on a 500V or higher range. Measure again with the black test lead attached to terminal 12 and the red lead attached to terminal 13.