re faulty crack [resolved]

[ross munro]

hi i have been using my crack for 2 years now and it has operated seemlessly however when i switched it on last night the volume was at maximum and heavily distorted,the volume control did not adjust it at all when i touched the top of the 12au7 valve everything returned to normal volume and the volume was working again this worked for about 5 minutes then the volume increased again to maximum and i had no control over it .it is now permanently at this extreme volume and heavily distorted.unfortunately due to my brain disease i can no longer solder or do checks on the unit due to extreme hand shaking. im based in the uk does anyone know of a good repair centre that could repair this for me as the 3 firms ive contacted so far wont touch it.is it possible the 12au7 valve is faulty7 although it lights up as normal.hoping you can help

regards mike haywood

 

[Paul Birkeland]

Does the volume go to full on both channels or just one channel?

This is a loose wire, definitely not a bad tube. 

 

[ross munro]

its on both channels extremely loud

 

[Paul Birkeland]

The black wire between the RCA jacks and volume pot is probably not connected well on one end, or possibly one of the other black wires attached to the pot.

 

[ross munro]

ok thanks paul i will very carefully re flow that wire many thanks for getting back to me so soon.i will let you know how it goes have a good day. speak soon

 

[ross munro]

ah sweet music once again thanks so much paul,you were right managed to re solder joint at volume pot and hey presto everything is good.im not sure if you know but a group of valve enthusiasts in the uk have obtained the original valve making machines and are producing new brimar valves to a very high standard including 300b,12au7 and many others the website is THE GREAT BRITISH VALVE PROJECT  i hope this is useful to you and doc b. once again thanks for the advice on how to fix my crack