Hacker Gondolier GP42 - UK Vintage Radio Repair and Restoration Discussion Forum

BRASSBITS · 30th Jun 2019, 6:48 pm

HI
can someone tell me what voltages
to expect on both ends of c6 and c7 caps
both are Mullard mustards
Mick

John10b · 30th Jun 2019, 7:19 pm

There are many posts relating to the Hacker, and in particular the two capacitors C6,7. I took a look at a few, I’m not particularly experienced on Hacker, and it seems they can be problematic, and worth replacing. One post said they had a high voltage on control grid ( over 100 volts) and after replacing the two capacitors the voltage was zero, “as it should be”.
The cathodes voltage is approximately +8volts.
I hope this helps but I’m sure some Hacker experts will give you much more advice.
Cheers
John

Nuvistor · 30th Jun 2019, 7:34 pm

Approx 145v+ on the anodes of the triodes, 0v on the control grids of the output pentodes.

BRASSBITS · 3rd Jul 2019, 4:40 pm

ok I have a strange fault on this gondolier
When switched on it makes the volume and treble controls seem noisy as tho they need cleaning,but there not.
I have just checked the voltages at the ends of the caps with valves removed and I get 313 volts dc
at the anode end and zero volts at the grid end
on both caps.
any ideas

Nuvistor · 3rd Jul 2019, 4:59 pm

The voltage will be high without the valves, those capacitors appear to be good which those Mullard ones usually are, but best to be sure by the tests you have performed.

The noise, I presume they are noisy after the valves have warmed up, does the noise stop after a few minutes or do they stay noisy?

BRASSBITS · 3rd Jul 2019, 5:02 pm

they stay noisy and when you turn the volume and treble along the lines of tuning a radio it brings on a motrboating noise

Nuvistor · 3rd Jul 2019, 5:44 pm

Presuming the circuit is has the original, check voltages on the valves, smoothing/ decoupling capacitors and components in the negative feedback circuit.

If the feedback only occurs with the lid down there are suggestions in the manual.

30th Jun 2019, 6:48 pm	#1
BRASSBITS Hexode Join Date: Dec 2018 Location: Sheffield, South Yorkshire, UK. Posts: 364	Hacker Gondolier GP42 HI can someone tell me what voltages to expect on both ends of c6 and c7 caps both are Mullard mustards Mick

30th Jun 2019, 7:19 pm	#2
John10b Nonode Join Date: Nov 2016 Location: Aberaeron, Ceredigion, Wales, UK. Posts: 2,887	Re: Hacker Gondolier GP42 There are many posts relating to the Hacker, and in particular the two capacitors C6,7. I took a look at a few, I’m not particularly experienced on Hacker, and it seems they can be problematic, and worth replacing. One post said they had a high voltage on control grid ( over 100 volts) and after replacing the two capacitors the voltage was zero, “as it should be”. The cathodes voltage is approximately +8volts. I hope this helps but I’m sure some Hacker experts will give you much more advice. Cheers John

30th Jun 2019, 7:34 pm	#3
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,433	Re: Hacker Gondolier GP42 Approx 145v+ on the anodes of the triodes, 0v on the control grids of the output pentodes. __________________ Frank

3rd Jul 2019, 4:40 pm	#4
BRASSBITS Hexode Join Date: Dec 2018 Location: Sheffield, South Yorkshire, UK. Posts: 364	Re: Hacker Gondolier GP42 ok I have a strange fault on this gondolier When switched on it makes the volume and treble controls seem noisy as tho they need cleaning,but there not. I have just checked the voltages at the ends of the caps with valves removed and I get 313 volts dc at the anode end and zero volts at the grid end on both caps. any ideas

3rd Jul 2019, 4:59 pm	#5
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,433	Re: Hacker Gondolier GP42 The voltage will be high without the valves, those capacitors appear to be good which those Mullard ones usually are, but best to be sure by the tests you have performed. The noise, I presume they are noisy after the valves have warmed up, does the noise stop after a few minutes or do they stay noisy? __________________ Frank

3rd Jul 2019, 5:02 pm	#6
BRASSBITS Hexode Join Date: Dec 2018 Location: Sheffield, South Yorkshire, UK. Posts: 364	Re: Hacker Gondolier GP42 they stay noisy and when you turn the volume and treble along the lines of tuning a radio it brings on a motrboating noise

3rd Jul 2019, 5:44 pm	#7
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,433	Re: Hacker Gondolier GP42 Presuming the circuit is has the original, check voltages on the valves, smoothing/ decoupling capacitors and components in the negative feedback circuit. If the feedback only occurs with the lid down there are suggestions in the manual. __________________ Frank