Hello. So I am the happy owner of a TA E86&TA N86 set and ever since I got the TA E86 preamp I have some strange issues with it, mainly when I cold start it.
After the 5-6 second delay from when I switch it on, there is a strong 1 minute of really strange noise, more specifically, there is some strong pink noise followed by a strange oscillating sound, just like when you play those 20hz -20khz sine waves, and then a pretty loud pop after which complete silence occurs. Turning it on and off after being on for some time does not replicate the sound. It only does this after it has been turned off for at least an hour or so.
The preamp has seen some servicing, some caps have been changed, but not all. To me, it sounds like a failing old cap that is charging, but looking at the schematics, after the 5-6 second mute sequence from the moment you power it on, there are three small caps on the power supply board that charge and those caps have been replaced.
I would appreciate a fresh input on the matter since it is pretty annoying and I really like this set so I want it fully working. Thank you!!
After the 5-6 second delay from when I switch it on, there is a strong 1 minute of really strange noise, more specifically, there is some strong pink noise followed by a strange oscillating sound, just like when you play those 20hz -20khz sine waves, and then a pretty loud pop after which complete silence occurs. Turning it on and off after being on for some time does not replicate the sound. It only does this after it has been turned off for at least an hour or so.
The preamp has seen some servicing, some caps have been changed, but not all. To me, it sounds like a failing old cap that is charging, but looking at the schematics, after the 5-6 second mute sequence from the moment you power it on, there are three small caps on the power supply board that charge and those caps have been replaced.
I would appreciate a fresh input on the matter since it is pretty annoying and I really like this set so I want it fully working. Thank you!!
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No scope limits diagnostics massively and leaves us guessing.
All that points to a PSU issue. You need to check these caps and also check the -/+29 volt rails are correct when the issue occurs. The phono stage has a similar PSU at lower voltage but your description suggests most likely the -/+ 29 volt reg is the area at fault.
A scope would help massively in something like this.
All that points to a PSU issue. You need to check these caps and also check the -/+29 volt rails are correct when the issue occurs. The phono stage has a similar PSU at lower voltage but your description suggests most likely the -/+ 29 volt reg is the area at fault.
A scope would help massively in something like this.
Those caps were changed by the tech who serviced the preamp. He also checked the voltages. Unfortunately I do not have any tools available, I rely solely on the tech that did the repair, but since we're both stuck and can't seem to figure out what's wrong, I decided to ask maybe you guys have some other perspectives
Had the same issue with my E86, both 3300u caps replaced (it was the neg-one!) & solved. This main +/-30Vdc regulator supplies the md-phono, line and BBoost amps.
Check for the other regulator +/-9Vdc circuit for the MC amp (on the phono board) - if there a main cap is overaged the common transformer is drowning.
These regulator circuits are both on the main pcb, and are wired under the pcb aka ground floor - so check for solderings also... ->
Most often the pre E86 is stacked upon the main N86 (RCA plugs orientation), which generates heat (a lot in A, less in AB), which deteriorates the lifespan of the caps in the E86. All alu & tant caps are vulnerable, if doubt replace with tropic grade (105°C) eqv's.
Lots of works, but these units are an almost immortal design & build until the silicon proton parts fall apart.
Check for the other regulator +/-9Vdc circuit for the MC amp (on the phono board) - if there a main cap is overaged the common transformer is drowning.
These regulator circuits are both on the main pcb, and are wired under the pcb aka ground floor - so check for solderings also... ->
Most often the pre E86 is stacked upon the main N86 (RCA plugs orientation), which generates heat (a lot in A, less in AB), which deteriorates the lifespan of the caps in the E86. All alu & tant caps are vulnerable, if doubt replace with tropic grade (105°C) eqv's.
Lots of works, but these units are an almost immortal design & build until the silicon proton parts fall apart.