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Old 19th Jan 2014, 7:19 pm   #161
kevinski
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Default Re: Pye Black Box

Main lead connectors measure 227v on/off switch measures 227v and the player voltage selector is still in the correct place.

Kevin
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Old 19th Jan 2014, 7:54 pm   #162
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Default Re: Pye Black Box

Looks like the laws of physics don't apply in Newcastle upon Tyne. 117 volts disappearing in a bit of wire?

Quote:
Voltage has dropped to 110v at primaries on mains transformer!
Do you actually mean the primary winding ie the one connected to the mains or are you talking about the secondary HT winding?
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Old 20th Jan 2014, 12:23 am   #163
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Default Re: Pye Black Box

The voltage at the PRIMARY is 110v.
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Old 20th Jan 2014, 10:00 am   #164
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Default Re: Pye Black Box

The only thing between the primary and the mains cable is the power switch. Seems odd, but wonder if that could be causing it? Could you try bypassing the switch maybe?
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Old 20th Jan 2014, 10:01 am   #165
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Default Re: Pye Black Box

Quote:
Originally Posted by Herald1360 View Post
Don't bin it.....

Someone here'll want it, even if only to find out what exactly is faulty!
Seconded. The Pye BB is a darn good machine.
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Old 21st Jan 2014, 1:43 pm   #166
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Default Re: Pye Black Box

Thirded. If it's really doing your head in, maybe look out for another amplifier - they do come up on eBay sites frequently enough. No point junking the cabinet, deck or speakers. You could then either keep the old amp for spares, or sell it as not working.
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Old 21st Jan 2014, 11:45 pm   #167
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Default Re: Pye Black Box

Kevin, if you're really at your wit's end with it, I could have a look at the amp for you. Have you a circuit diagram for it? If so send me a PM and I'll see what I can do. I would hate to see you give up on this one!
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Old 22nd Jan 2014, 5:05 pm   #168
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Default Re: Pye Black Box

Here are two pictures to illustrate the problem I seem to be having. First photo is the voltage at the on/off switch - 234Vac, second photo 113Vac at the transformer primaries. Any help identifying whether I'm doing something wrong or if the transformer's goosed, or the On/Off switch is broken would be much appreciated.

Thanks

Kevin
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Old 22nd Jan 2014, 5:34 pm   #169
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Default Re: Pye Black Box

You need to check the voltage at both the input and output of the OFF/ON switch. If the reading at the output is 117V, then the switch is faulty.

If the reading at the output is 234V the switch is OK and it's possible the voltage selector isn't making good contact.

You talk of transformer PRIMARIES ie plural. If there are two primary windings which can be wired in series or parallel, they'll be wired in series for the UK mains voltage and you will see 117V across each winding.

Is it just coincidence that 117V is exactly half 234V?
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Old 22nd Jan 2014, 5:53 pm   #170
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Default Re: Pye Black Box

A better description would be the primary tags. The voltage at the input and output of the switch is 234v. I have cleaned and made sure the voltage selector is making good contact and still the same results.

Kevin
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Old 22nd Jan 2014, 5:58 pm   #171
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Default Re: Pye Black Box

So there is only one primary winding?

You need to find out where the volt drop is occurring.

Clip one meter lead to the neutral side of the mains cable where it is first terminated inside the player. Probably on the OFF/ON switch. Meter set to AC volts, switch on the player. Use the other lead to probe each point in the primary circuit. You should only see a volt drop across the primary winding. In your case you're ging to see a 117V drop elsewhere. That'll be where the fault is.
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Old 22nd Jan 2014, 8:27 pm   #172
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Default Re: Pye Black Box

Quote:
Originally Posted by Station X View Post
So there is only one primary winding?
The 0V end and the 3 tap wires can be seen in the photos of the transformer, are you testing from the correct point? I can't see how else you are getting 117V at the primary. If it was open circuit you would get 240V, if it had shorted turns I would expect would get smoking/ overheating/ blown fuses.

Are the heaters lit?
see here:
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Old 22nd Jan 2014, 8:45 pm   #173
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Default Re: Pye Black Box

Hi, Kevin. Are you sure you are probing the right terminal on the transformer? I wouldn't expect the 240v tap to be next to the 0v tap. Try probing the next 2 taps with one probe whilst leaving the other connected to the white wire tap.

I could be completely wrong though but it's just my observation.

David.
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Old 22nd Jan 2014, 9:35 pm   #174
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Default Re: Pye Black Box

Kevin, with the unit unplugged, the deck motor unplugged, and the power switch in the on position, and the voltage selector on its highest range, connect a resistance meter to the L & N terminals of the mains plug.

What reading do you get?

According to the manual, it should be roughly 38 ohms.

Nick.
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Old 22nd Jan 2014, 10:21 pm   #175
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Default Re: Pye Black Box

According to that circuit snippet, there's a 110V tap on the TX primary. If you measure the voltage between that tap and neutral (or live) end of the primary, you'll get that 117V!
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Old 22nd Jan 2014, 10:46 pm   #176
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Default Re: Pye Black Box

David - reading from the bottom tag (white) up
Tag 2 = 115Vac
Tag 3 = 212Vac
Tag 4 = 238Vac
Tag 5 = 5Vac
Tag 6 = Ov

Nick - I measure 39Ω's at the plug terminals

Thanks

Kevin
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Old 22nd Jan 2014, 10:49 pm   #177
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Default Re: Pye Black Box

Looks like we're back at post #159 then.

Quote:
Originally Posted by kevinski
That's it!! I give up!! . Tried the thing again this morning and no sound!. Voltage has dropped to 110v at primaries on mains transformer! Getting 43vdc at the rectifier. Tried a new rectifier and the same. Time to put it in the bin and try a different machine. Thanks to all for your help, hopefully I have learned a lot from this experience.

Kevin.
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Old 22nd Jan 2014, 10:56 pm   #178
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Default Re: Pye Black Box

Quote:
Originally Posted by kevinski View Post
David - reading from the bottom tag (white) up
Tag 2 = 115Vac
Tag 3 = 212Vac
Tag 4 = 238Vac
Tag 5 = 5Vac
Tag 6 = Ov

Nick - I measure 39Ω's at the plug terminals
Kevin, this proves that mains is getting to the primary of the mains transformer OK.

Is the pilot light lit?

N.
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Old 22nd Jan 2014, 11:06 pm   #179
kevinski
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Pilot light is lit
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Old 22nd Jan 2014, 11:12 pm   #180
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Default Re: Pye Black Box

If the pilot light is lit, then the transformer is getting power and working.

You should see the valves lighting up. You shuld also be able to measure HT approx 280V across the reservoir capacitor.

Did you replace the bridge rectifier?
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