Bogner alchemist stucked on clean channel

[Nicale19]

Hi to all,


I have experience in electronics and tube amplifier repair, but all these semi-digital electronics confuse me a bit

This is the story of this alchemist :

I restored  power supply back on it, the amplifier was working fine but with a lot of hum
I increased the filter capacitors in the while (220*2/100*2 500v)
Changed rectifier diode and capacitor 68000uf.
The amplifier was fine.

Playing today, after some day that as i said amp was ok, I heard a short and A small spark circuit somewhere and the amp got stuck on the clean channel
Only clean channel commands work, the relative switches treble crunch deep are ok
Digital effects work
I've checked voltage and they seem ok, so the power supply seems to be good. I'm afraid that some component in the relay circuit has blown
Tomorrow I will recheck the digital board from which the inputs for the channel change relays start (the one where the 7905/08 transistors are present, etc
I replaced q1/q2 with two transistors 2n3904

I'm trying everything, there are no burn marks, the only component that was blown is r4 apparently
I replaced it
Maybe I was tired and stressed and I got the wrong value
A little while ago I was reading is 1k
I'm afraid I used a superior value.
Any idea is wellcome

[Nicale19]

Meanwhile I found the error, r4 should have been replaced with a 1m resistor and instead I had entered an incorrect value
I still can't test because in the meantime I had disassembled all the power supply and I'm going to replace c6/c11/d7 because they had aged
The disassembled capacitors gave readings values other than the nominal ones
If there was no problem at the level of dsp (and I don't think so) somehow calmly I will be able to get out of it

[Latole]

Service manual ; https://el34world.com/charts/Schematics/Files/_miscellaneous/Line_6_alchemist_sm.pdf

[Nicale19]

Service manual ; https://el34world.com/charts/Schematics/Files/_miscellaneous/Line_6_alchemist_sm.pdf

Thank you.

I own it and I am studying it, obviously mine is amateur knowledge of repair, I have read that around these problems are unfortunately frequent, if someone with more experience than me could direct me, I would be grateful. Of course, in the meantime I share my progress

[Latole]

I post schematic because if you ask some help, we need to see schematic.

Don't increase filter caps value, change for same if they are no good.

Always tell tell us witch component you are talking about :  C1...C1 , D9 .....

[Nicale19]

I post schematic because if you ask some help, we need to see schematic.

Don't increase filter caps value, change for same if they are no good.

Always tell tell us witch component you are talking about :  C1...C1 , D9 .....

Ok clear
A few days ago I had changed C7(same 68000 16v)Taking advantage of the pcb opening I replaced
C8/c9/c10/c11
(100/220/100/220uf 500v)

The amp was fine, sounded very good full on bass
The only initial oddity was putting 6l6 mesa boogie (which used to work) I noticed a flickering of the relays.
I had removed the 6l6 mesa boogie and put the original 5881 back on. Everything was going wonderfully
During a test I felt a spark and r4(1mb) jumped near the Z0109 (q1) triac.
The clean channel remains active together with the boost mode
None of the fun switched works,
The sound comes out well together with the delay and reverb effects.
Now I have further disassembled the power supply board and I have desoldered c6/c11 (4700/35v 1000uf/50v)
I tested these components and they no longer had declared values.

I know that the power supply system of the relays is very delicate on this amplifier.

In any case, I believe that something around the Z0109 must have undergone some strange abnormal tension

[Nicale19]

First problems found, there was no conduction between the rectifoer - of the d7 and - of c7

[Nicale19]

The problem has not been resolved.

I noticed that +18v was in contact with a ground mass.
There's something strange about the capacitor c6, It would seem to be short

[Latole]

The problem has not been resolved.

I noticed that +18v was in contact with a ground mass.
There's something strange about the capacitor c6, It would seem to be short

It may require a good knowledge of electronics

[Nicale19]

The problem has not been resolved.

I noticed that +18v was in contact with a ground mass.
There's something strange about the capacitor c6, It would seem to be short

It may require a good knowledge of electronics

Is it a way of saying to let it go? 😅

[tubeswell]

Service manual ; https://el34world.com/charts/Schematics/Files/_miscellaneous/Line_6_alchemist_sm.pdf

discombobulated deconstructed schematics give me ADHD LoL

[Nicale19]

Service manual ; https://el34world.com/charts/Schematics/Files/_miscellaneous/Line_6_alchemist_sm.pdf

discombobulated deconstructed schematics give me ADHD LoL

 

[jjasilli]

It's not clear to me that many new amps are susceptible to being repaired.  The same has happened in the auto industry.  Even skilled independent mechanics can't or won't do repairs.


The problem is that the dams things are being built.

[AlNewman]

Sometimes solid state can be a fairly easy fix, it almost always requires at least a bit of electronic knowledge and equipment.
When it isn't easy, it's basically planned obsolescence, depending on what your time and sanity is worth.

[Nicale19]

Caps changed

Voltages Ok

Same problem.

The voltages on the logic board are also ok

(3,3/5/1,65/8/15/8)

The boost is always on, the clean is always on

[Nicale19]

How do you consider such resistance even though it marks apparently ok value?

[Nicale19]

Ok

[Nicale19]

K2 k10 k11 no sign of switch (using 4,5v)
K7 works
ALL Other releys are ok