at this point putting power to this poor thing is a recipe for more heartbreak/cost finding out whether or nor the pass transistor survived and if the zener is a short or open is what should happen but others known more,i digress...
Hi every one ,
I would like to say a huge thank you to all you guys for your help !
i finally repaired that poor amp who spend a year in the garage, and only recently I finally found time to get back into it, and help by your valuable advices , i made it work again properly.
So for the answer, i found out 3 pieces were faulty : the TR7 , the zener Z3 and also the bubbling C16.
I changed them all . The voltage on that part of the board went back to normal ( 16 v , I would have prefered a 12 v but then), I installed a new fan, and the beast is now handling hours of playing heavy roots reggae dub !
Long live diyAudio !
I would like to say a huge thank you to all you guys for your help !
i finally repaired that poor amp who spend a year in the garage, and only recently I finally found time to get back into it, and help by your valuable advices , i made it work again properly.
So for the answer, i found out 3 pieces were faulty : the TR7 , the zener Z3 and also the bubbling C16.
I changed them all . The voltage on that part of the board went back to normal ( 16 v , I would have prefered a 12 v but then), I installed a new fan, and the beast is now handling hours of playing heavy roots reggae dub !
Long live diyAudio !
The power amp section is a direct copy of the venerable Maplin kit of 1980something! Just higher voltage rails and two pairs of output devices.
Funny, I built one when they were first available and used it for a bass amp for years. Who'd have thought, I was first on my block with a Trace...even had a graphic equaliser that I used to suck all the middle out.
I lent it to a DJ one time and he ran it into 2 ohms all night. The heatsink was too hot to touch but it lived.
Hi everyone , i'm happy to find your discussion, as i have a Trace Elliot bass amp - AH300 SMC GP7 and i'm fond of it with bass of course but for my part with guitar ...recently i made a stupid thing :when i smelt a strange odor coming through the ventilator ...after openning it i touch a module with a screwdriver whereas it was light on which makes a breakdown . Now i must immediatly say that i 'm musician and my knowledges of electronic composants & structures&...are very very limited.... yesterday i used to call audiotronics (in bordeaux) for this sort of problem but they stopped their service ... so i let my precious amp in a bordeaux shop ...the guy calls me one month later explaining it was'nt repairable cause it concerns 4 transistors side by side obsolete !!! i find this really incredible and i doubt of the honesty of that reasoning process.Moreover i realised the fact that the smell was'nt coming from it ....i go today get back my amp i will ask him of course precisions.
Please could be someone telling me that we could change or find transitors to repare it ? i know that there are plenty tansistors...
I love the sound of it for plenty reasons....i can't accept it will not work !
if you have address of specialist or...you're welcome !
Thanks to the community and for your comprehension
Kussjungle
Please could be someone telling me that we could change or find transitors to repare it ? i know that there are plenty tansistors...
I love the sound of it for plenty reasons....i can't accept it will not work !
if you have address of specialist or...you're welcome !
Thanks to the community and for your comprehension
Kussjungle
These would be the output FETs, and though they're obsolete I believe Profusion sell direct equivalents
https://www.profusionplc.com/parts/ecx10n20
Hopefully someone can confirm
https://www.profusionplc.com/parts/ecx10n20
Hopefully someone can confirm
That guy was being honest, the original transistors are unavailable, not manufactured for decades or at best horribly expensive IF you find s couple.
Not these 🙁
Luckily there is one manufacturer (Profusion PLC in GB) making compatible ones ... not sure for how long.
So: repair it now, or maybe in the future you will not be able to any more.
I have repaired some, also other 80´s amps where Hitachi MosFets were all the rage, but had to modify and convert them to available IRFP240/9240
Not the same nor direct equivalent by any means, requires some brain surgery, not for the faint of heart, and in any case can´t offer my services since we are 10000 km away so do yourself a favour and get those Profusion MosFets today 😉