DSL100H Output problem

Texden

New Member
Joined
Jan 18, 2022
Messages
3
Reaction score
2
I have a DSL 100H head,I took it off standby and have no output,if I dime the volume control, I get a faint output (barely audible)from the 4/12 cab, I took the chassis out and found no fuses blown,and all preamp and power amp tubes glow! I ordered a new set of tubes for it,but power tubes are on back order,I tried the guitar in the effects return and get nothing.I did find R68 and R67 burnt (they were touching each other)
,but those go to the bias testing post,from what I can tell.What else should I check?
 

Chris-in-LA

Well-Known Member
Joined
Jul 19, 2018
Messages
3,308
Reaction score
3,418
Location
Los Angeles
I have a DSL 100H head,I took it off standby and have no output,if I dime the volume control, I get a faint output (barely audible)from the 4/12 cab, I took the chassis out and found no fuses blown,and all preamp and power amp tubes glow! I ordered a new set of tubes for it,but power tubes are on back order,I tried the guitar in the effects return and get nothing.I did find R68 and R67 burnt (they were touching each other)
,but those go to the bias testing post,from what I can tell.What else should I check?
If R67 and R68 are the 1ohm resistors in the bias circuit and they burned, your power tubes may have lost their ground. Normally, an el34 has pins 1 and 8 grounded, either with a wire or the 1ohm resistor.
 

South Park

Well-Known Member
Joined
Sep 14, 2019
Messages
3,988
Reaction score
3,852
You are getting noice so that means the out put section is working and not blowing fuses no shorts. Check all the plates for power
 

Pete Farrington

Well-Known Member
Joined
Jan 18, 2021
Messages
1,443
Reaction score
1,591
Location
Staffordshire UK
I’m getting continuity (voltage)through them
So is that continuity, ie a resistance measurement, or are you measuring voltage on both terminals of each fuse?
The requirement is to take the fuse out of the fuseholder and check its resistance.
Checking for voltage or otherwise measuring it in circuit may not give the results you might expect.
 

Texden

New Member
Joined
Jan 18, 2022
Messages
3
Reaction score
2
So is that continuity, ie a resistance measurement, or are you measuring voltage on both terminals of each fuse?
The requirement is to take the fuse out of the fuseholder and check its resistance.
Checking for voltage or otherwise measuring it in circuit may not give the results you might expect.
I’ll pull them and check resistance through them tonight,I checked voltage on each side of the fuses
 


Top