Hello.
Reciver YAMAHA DSP A 1.
Shut off after 2 seconds.
No speakers,no suspect parts.
LCD display OK.
All fuses OK.
Diag mode not possible..
Thanks
Service manual
YAMAHA DSP-A1 SM Service Manual download, schematics, eeprom, repair info for electronics experts
Reciver YAMAHA DSP A 1.
Shut off after 2 seconds.
No speakers,no suspect parts.
LCD display OK.
All fuses OK.
Diag mode not possible..
Thanks
Service manual
YAMAHA DSP-A1 SM Service Manual download, schematics, eeprom, repair info for electronics experts
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As its processor controlled and the diagnostic menu doesn't show up yet the display is okay but shuts off after 2 seconds you have a choice -- faulty output device -part of the power supply is faulty - high offset and so on.
You could spend a lot of time (and money ) tracing this,even your link says it could be several things and with no diagnose menu to look at all you can do is check all the output devices and check the power supply components .
But you say---"no suspect parts" you know then that it could be a fault related to the safety cut-out and or the processor itself ?
Looking at the PCB it must have taken you a long time to check out ALL the active components ?
You could spend a lot of time (and money ) tracing this,even your link says it could be several things and with no diagnose menu to look at all you can do is check all the output devices and check the power supply components .
But you say---"no suspect parts" you know then that it could be a fault related to the safety cut-out and or the processor itself ?
Looking at the PCB it must have taken you a long time to check out ALL the active components ?
The problem with complicated processor controlled AV equipment is that tracing faults on them isn't a simple job that's why a fault menu is part of the receiver but yours doesn't work.
At least the cut out works so in your position I would look for a short circuit in one of the output devices for a start and then check out all the power supply active components but sorry I cant pin this down for you even if I had it on my bench I would need to spend some time tracing the fault .
At least the cut out works so in your position I would look for a short circuit in one of the output devices for a start and then check out all the power supply active components but sorry I cant pin this down for you even if I had it on my bench I would need to spend some time tracing the fault .
Is it a more than 20 years old unit? On the internet, for DSP A1, I've found: "99% its blown capacitor which results to damaging IC controller as well."
If its the case, you may have to check or replace all electrolytic capacitors. They may have aged out, won't look burnt, maybe some are deformed.
If its the case, you may have to check or replace all electrolytic capacitors. They may have aged out, won't look burnt, maybe some are deformed.
The last time I had to swap out capacitors, it was for my kitchen oven. None seemed faulty, but the electronic/clock didn't start... I swapped them all. That was easy, only some 3 to 4 to swap.
I've an old Denon amp, some 25-30 years old, which started to make noise on power up, sort of hiss for some minutes, then no more noise (old caps may need some time to heat up). At the end, the noise went constant. I think I would have to change all its caps to recover it.
Either you notice some deformed caps, change those, or change them all.
I've an old Denon amp, some 25-30 years old, which started to make noise on power up, sort of hiss for some minutes, then no more noise (old caps may need some time to heat up). At the end, the noise went constant. I think I would have to change all its caps to recover it.
Either you notice some deformed caps, change those, or change them all.
You should get +/-47.7 volts DC after the rectifier in one supply and +/- 27.3 volts DC on the other supply after the rectifier.
If a capacitor is aged out somewhere, main PSU voltages can seem correct.
You have the service manual. Look for schematics plus PCB descriptions, and power supply lines, of amplifiers, of preamps, of you controller and front panel indicator. If it is Ok at the PSU side, check all those other power rails.
Do not make any short circuit with your test pins doing this. You could connect one test pin to 0V, and move only the other test pin around.
After main PSU, you will probably find +/-15V for preamps and +5V for the controller.
You have the service manual. Look for schematics plus PCB descriptions, and power supply lines, of amplifiers, of preamps, of you controller and front panel indicator. If it is Ok at the PSU side, check all those other power rails.
Do not make any short circuit with your test pins doing this. You could connect one test pin to 0V, and move only the other test pin around.
After main PSU, you will probably find +/-15V for preamps and +5V for the controller.
You say it is turning of two seconds after power on, that could be positive.
See page 12 of your manual: it can activate a protection mode.
Depending of the fault, software may not be able to show you what is wrong.
I saw it has a lot of VR/adustable resistors inside. Do no touch or turn any of those. First just use your voltmeter test pins to check power supplies. By the way, look again at capacitors, if all have the same and correct shape.
Post some pictures with capacitors. How old is that unit?
Look around pages 43-44. There I see +5 +15 -15, that could be power lines. Before connecting probe pin, have a look at wire colors, and components around. If you have capacitors close to +5, you could check if those capacitors are at +5V.
After the PCB pages, for confirmation, look at all the schematics pages for power lines, here from page 53. Looks like +15 and -15 correspond to power lines you could test.
See page 12 of your manual: it can activate a protection mode.
Depending of the fault, software may not be able to show you what is wrong.
I saw it has a lot of VR/adustable resistors inside. Do no touch or turn any of those. First just use your voltmeter test pins to check power supplies. By the way, look again at capacitors, if all have the same and correct shape.
Post some pictures with capacitors. How old is that unit?
Look around pages 43-44. There I see +5 +15 -15, that could be power lines. Before connecting probe pin, have a look at wire colors, and components around. If you have capacitors close to +5, you could check if those capacitors are at +5V.
After the PCB pages, for confirmation, look at all the schematics pages for power lines, here from page 53. Looks like +15 and -15 correspond to power lines you could test.
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have confidence, trust yourself, use your skill learned from your experience in fixing >5 defective amps in the past 5 months.
you have tools like DVM, parts checker, even a de-soldering blower.....one more scope will be perfect.
go a higher level, do the necessary basic checks before your come up with questions you never met.
the procedure of fixing different amps are almost the same,
know the schematic, eye examine, supplies, voltages, bad joints, defective transistors, diodes, capacitors, bad connections, groundings...
care, patience and skills are also needed.
hope you fix it soon.
you have tools like DVM, parts checker, even a de-soldering blower.....one more scope will be perfect.
go a higher level, do the necessary basic checks before your come up with questions you never met.
the procedure of fixing different amps are almost the same,
know the schematic, eye examine, supplies, voltages, bad joints, defective transistors, diodes, capacitors, bad connections, groundings...
care, patience and skills are also needed.
hope you fix it soon.
ОK,thank you very very much.
I will test all necessary, regards.
Its my hobby.
I like saved hi-fi engines from garbage
I will test all necessary, regards.
Its my hobby.
I like saved hi-fi engines from garbage
I didn't check, if software would power up or down parts of that box. You may have to study the schematics, if some relays exist, or if regulators have an enable/disable pin.
Maybe start by checking around the controller board, if its 5V is clean.
Maybe start by checking around the controller board, if its 5V is clean.
On C111.....+55.6v
On C112......-55.7v
On C113.......31.1v
On C114........-31.1v
To be continued
On C112......-55.7v
On C113.......31.1v
On C114........-31.1v
To be continued
-15v......-14.5v
+15v.........+14.5v
I can take measurements in two seconds while the amplifier is on. After shutdown, everything drops to zero.
+15v.........+14.5v
I can take measurements in two seconds while the amplifier is on. After shutdown, everything drops to zero.
please take extreme care to check your mains AC voltage. it could be fatal.
if you already know the mains voltage, don't touch it.
check the primary settings of your transformers if they match the mains ac voltage.
it could be a mismatch of the ac voltage or the transformer is not working properly.
******
the voltages on C111-C114 are too high.
the voltages on C111, C112 should be around +/- 47.5v according to the schematic.
and C113, C114 should be around +/- 27.2v
the +/-15v, 5v are ok because they were regulated.
take care, you are dealing with ac mains and its dangerous to handle.
if you already know the mains voltage, don't touch it.
check the primary settings of your transformers if they match the mains ac voltage.
it could be a mismatch of the ac voltage or the transformer is not working properly.
******
the voltages on C111-C114 are too high.
the voltages on C111, C112 should be around +/- 47.5v according to the schematic.
and C113, C114 should be around +/- 27.2v
the +/-15v, 5v are ok because they were regulated.
take care, you are dealing with ac mains and its dangerous to handle.