Laney amp repair advice needed

[stevekendal]

The front end of my Laney DP150 has given up the ghost If there is anyone viewng who can offer direct help, I have the schematic here and test equipment. Cheers, Steve.

[Dandelion]

Rusty input jack?

[Musky]

[quote name='Dandelion' post='924470' date='Aug 13 2010, 10:40 PM']Rusty input jack?[/quote]
+1

[stevekendal]

Cheers for those gems guys. The fault is a little more involved than that and I was hoping for advice from a tech, rather than Russel Brands' scriptwriter

[Musky]

Seriously. I and others on this site have had the front end of Laneys pack up because of dirty contacts on the input jack. Maybe you could describe the problem in a bit more detail and someone might have other suggestions?

[stevekendal]

[quote name='Musky' post='924855' date='Aug 14 2010, 01:21 PM']Seriously. I and others on this site have had the front end of Laneys pack up because of dirty contacts on the input jack. Maybe you could describe the problem in a bit more detail and someone might have other suggestions?[/quote]


Ok, It atarted off being intermittent and now there is no signal getting through at all. If the gain controls are backed off, a loud squeal comes through. The input overload light is on all the time even with nothing plugged in. Steve. Ps, I have the circuit diagram, but it wont post on here, just e mails ok.

Edited August 14, 2010 by stevekendal

[Subthumper]

[quote name='stevekendal' post='924870' date='Aug 14 2010, 01:50 PM']Ok, It atarted off being intermittent and now there is no signal getting through at all. If the gain controls are backed off, a loud squeal comes through. The input overload light is on all the time even with nothing plugged in. Steve. Ps, I have the circuit diagram, but it wont post on here, just e mails ok.[/quote]


Hi, it sounds like you've got a chip gone dud on you somewhere in the pre amp circuit. Not sure which ones the laney has but they dont cost much and if your lucky they'll be on chip sockets so should be easy to swap out. Dont forget to note which way round they're fitted. If you're in or near Bristol PM me, I run an amp repair business.
Good luck cheers Just

[Mr. Foxen]

[quote name='Dandelion' post='924470' date='Aug 13 2010, 10:40 PM']Rusty input jack?[/quote]

Euphemism.

[umph]

[quote name='Subthumper' post='925159' date='Aug 14 2010, 08:17 PM']Hi, it sounds like you've got a chip gone dud on you somewhere in the pre amp circuit. Not sure which ones the laney has but they dont cost much and if your lucky they'll be on chip sockets so should be easy to swap out. Dont forget to note which way round they're fitted. If you're in or near Bristol PM me, I run an amp repair business.
Good luck cheers Just[/quote]
hopefully that, sounds like somethings causing one to oscillate anyway. Best to bust out the signal generator etc and see where it's starting

[stevekendal]

[quote name='Subthumper' post='925159' date='Aug 14 2010, 08:17 PM']Hi, it sounds like you've got a chip gone dud on you somewhere in the pre amp circuit. Not sure which ones the laney has but they dont cost much and if your lucky they'll be on chip sockets so should be easy to swap out. Dont forget to note which way round they're fitted. If you're in or near Bristol PM me, I run an amp repair business.
Good luck cheers Just[/quote]


No they're not dear, but they are soldered directly to the board and there's about 20 of them! Which one might cause the OL light to come on? Fraid I'm too far from Bristol (Kendal)

[Subthumper]

[quote name='stevekendal' post='925974' date='Aug 15 2010, 11:07 PM']No they're not dear, but they are soldered directly to the board and there's about 20 of them! Which one might cause the OL light to come on? Fraid I'm too far from Bristol (Kendal)[/quote]

Ok then its time to start going through the schematic and looking at what components are associated with the overload led. Sometimes it can be cut and try with fault finding although if you have or have access to an oscilloscope and a signal generator you can chase the signal through the circuit and see where its going wrong.
If your really stuck and it seems like your going to have to take it to a techie then dont do anything to it as this can make for a hard time for the repair man. ie not knowing if he's looking for a fault or if he's trying to fix what you've messed up.
Good luck
Cheers Just