Hello to everybody from Belgrade, Serbia.
Last month I bought this extraordinary second hand guitar amp in very good condition, here in Serbia,(import from Germany) but there is ,,minor" electronic issue...this amp has no distortion channel at all. Somebody in Germany did some ,,surgery" on this amp and eliminated a few transistors, diodes, resistors and OD switch from the PC board completely, drilled the front panel above the missing OD switch and installed one more input jack.Jack is wired inside with half of that same missing parts from board and that second channel actually works! But only if you plugged in that added input socket...so, this amp now has two independent clean channels.
Really don't know the reason why somebody, ,,butchered" this piece of art, maybe converted this classic guitar amp into an acoustic amp with artificial input for mic or something else. On the PC board there is no burning traces.
My question is: Can anybody help me with this? I really wanna fix that amp and convert him into the previous condition. I can't find anything about fixing this amp on the internet, especially missing schematics and service manuals.
Without this data, my hands are tights. I am already taking precise foto what parts are missing and what parts are dislocated to be funkcional.
Massive thanks in advance!
Please share some detailed pictures of the inside of the amplifier and we may be able to help you trace the circuit and figure it out.
Closest I have
Thank You Tassieviking, that is schematic for glx 100/150 and I have it. :tu:
Quote from: joecool85 on December 10, 2024, 06:54:07 PMPlease share some detailed pictures of the inside of the amplifier and we may be able to help you trace the circuit and figure it out.
https://drive.google.com/file/d/1Mt3zZf9n6DnZ6pZBorDZq_0uV7it3KEg/view?usp=sharing (https://drive.google.com/file/d/1Mt3zZf9n6DnZ6pZBorDZq_0uV7it3KEg/view?usp=sharing)
Please open link with pictures. On 3 of them you can see Marshall Valvestate mk1 switch button ( just for testing, perfect fit) on empty SW2 position. Diodes Z2, D8 and D9 are there, but simply cut. Missing all 5 transistors - TR1,2,3,4 and 5. Some diodes are relocated from above and solder to under PC board...some resistor and block condenser too. Resistors around missing OD switch SW2 are used for new input connection...I am here for questions.
There is some kind of problem or restriction with that google drive page.
I supply my own google ID which always works and it is not vccepted
You should make it available for anybody.
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They tell me to send you an email asking for permission which is not the way to go.
Quote from: J M Fahey on December 11, 2024, 05:45:07 PMThere is some kind of problem or restriction with that google drive page.
I supply my own google ID which always works and it is not vccepted
You should make it available for anybody.
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They tell me to send you an email asking for permission which is not the way to go.
Link solved...please, try again.
Ok, now I can see them.
Others may differ, personally think earlier owner **butchered** that nice little amp.
IF it had plain failed under use, and nobody touched it, even without schematic we would have a reasonable possibility of repair, by measuring bad parts , unexpected voltages, looking for cracked solder or tracks, overheated but readable parts, normal *repair* procedure, but here the only word that applies is butchered.
We do not know the original circuit, which could help even if "painting by the numbers", meaning putting every part where it belongs following schematic.
On the other side we do not have "bad parts" which can be tested and worst case blindly replaced (we call that shotgunning) but MISSING parts, many of them.
1 or 2 missing might be guessed, suppose somebody pulled a transistor for testing and didn´t replace it, but not 10-15-20 parts at random.
Besides that, there is also path rerouting and PCB modding to further complicate things.
Least damage path would be to use it as-is, and add pedals as needed.
Suggest you keep searching for the original schematic and when/if you find it, post it here, we will be happy to help.
Pity, it looks like a very well made and nice amplifier.
J M Fahey, thank you for your time and your opinion...and yes, this amp is excellent made. That is way it looks soo good and after 30 years...truly competition to Marshall Valvestate V40, just without a tube in pre-amp section.
You have probably spent much time looking for schematics on line, but have you searched much for pictures of the insides?
Thank You for suggestion, but almost nobody mention this model anywhere...mostly older tube amp heads repair on YT. Only a few videos how it works and that´s it.
Just curious, did you try *writing* Carlsbro themselves?
The Factory or head office itself.
I guess they changed hands since (investors will buy *anything*) but they might have inherited a bookshelf of old dusty prints, who knows?
I know current Carlsbro products include generic Chinese made powered PA speakers. but hey ...
Please post photos of the whole foil side and the whole component side.
The close-ups are too close to understand anything.
Quote from: J M Fahey on December 14, 2024, 11:08:24 AMJust curious, did you try *writing* Carlsbro themselves?
The Factory or head office itself.
I guess they changed hands since (investors will buy *anything*) but they might have inherited a bookshelf of old dusty prints, who knows?
I know current Carlsbro products include generic Chinese made powered PA speakers. but hey ...
Yes, I tried, but there is nothing about their own products from 20th century on Carlsbro.com/support.
Quote from: dmeek on December 14, 2024, 11:44:03 AMPlease post photos of the whole foil side and the whole component side.
The close-ups are too close to understand anything.
Ok,I´ll do it as soon as possible.
Quote from: Zzmegi on December 14, 2024, 01:23:11 PMQuote from: J M Fahey on December 14, 2024, 11:08:24 AMJust curious, did you try *writing* Carlsbro themselves?
The Factory or head office itself.
I guess they changed hands since (investors will buy *anything*) but they might have inherited a bookshelf of old dusty prints, who knows?
I know current Carlsbro products include generic Chinese made powered PA speakers. but hey ...
Yes, I tried, but there is nothing about their own products from 20th century on Carlsbro.com/support.
I didn´t suggest "look at their Manuals page" but *write* them ;)
Very politely and with lots of smiles, asking something like "I have one of your Legacy products xxxxxxx which I like very much, maybe by any chance you could have its schematic stored somewhere?
It would be of great help to me. Thanks"
Or something like that.