petehall347
the brandy coffee man
i see the 780 AC supply to pin 7 starting off higher than the 980 so i give up .. end of the day pin 7 needs nice AC by the looks of it .
Pioneer SX-980 Protection Relay Kicking Out
- Thread starter Brivan
- Start date
AFAIK yes.
9 hours and still going. I think I'll stash it back in the rack since the grandkids are showing up tomorrow. They are disciplined well enough to avoid tampering with aything in my work area, but a receiver sitting in their play room might be fair game.
Regarding the presence of AC at PA3004, what little I know is that the schematics I have indicate 0.75VAC at Pin 7. Look within the outline of the PA3004 itself:
Regarding the presence of AC at PA3004, what little I know is that the schematics I have indicate 0.75VAC at Pin 7. Look within the outline of the PA3004 itself:
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And people wonder why critical systems still use 4-20mA loops for process signals instead of ethernet I/P as seems to be preferred by those not working in critical systems. For example, there are no I/P instruments (nor PLC or even PC control) in power generating stations, combustion systems, refining PIDs, or at least not in the critical processes. There are lots of examples of those in support systems like HVAC, building security, utilities, data collection, etc, but not in the critical processes. There is an increasing noise threshold in lots of systems and equipment, and it is NOT getting any better. 40+ years ago electrical engineers probably expected that things would get better, not worse, but they probably never anticipated the accountants and MBAs running everything.
Brivan
Well-Known Member
With R11 bypassed and R12 removed, the cycling stopped with the relay closed (pulled in). Also, FWIW, I haven't looked to see what an SX-5580 (European equivalent of an SX-1050) uses in its protection circuit, but I had mine in the shop shortly before the SX-980, and it behaved normally.
Brivan
Well-Known Member
I guess 0v at pin 7 of the PA3004 is technically correct, if only for a few seconds but, as MTF pointed out, it is misleading. If the individual outline of the PA3004 is correct, that helps. Luckily, in the SX-980 schematic, the voltages are correct in both places.9 hours and still going. I think I'll stash it back in the rack since the grandkids are showing up tomorrow. They are disciplined well enough to avoid tampering with aything in my work area, but a receiver sitting in their play room might be fair game.
Regarding the presence of AC at PA3004, what little I know is that the schematics I have indicate 0.75VAC at Pin 7. Look within the outline of the PA3004 itself:
Brivan
Well-Known Member
M
Makes me wonder what other kind of silly issues we're having that I'm not aware of. Next time I see one of the Maintenance fellas, I'll ask.
Brivan
Well-Known Member
Unrelated to this topic, but since I got educated about a dim bulb tester during this lengthy thread, I thought I'd put a link here. Today, I completed my retro-style dim bulb tester. AK link below:
http://audiokarma.org/forums/index.php?threads/retro-style-dim-bulb-tester.840697/
http://audiokarma.org/forums/index.php?threads/retro-style-dim-bulb-tester.840697/
Brivan
Well-Known Member
Just an update to this thread: I recently acquired another Pioneer SX-980 that was in protection mode when I received it. After replacing a few bad components on the power supply board, the protection relay engaged. That was with the receiver plugged into the DBT. I plugged it into wall power and the protection relay started to cycle - same as the other two SX-980s I had in the shop. With experience under my belt, I'm not sweating it - I know it will work just fine when I get it home.
DBCVette95
New Member
I am new to this, I am a retired electrics tech. I am troubleshooting a SX-980. All the voltages appear to be good, The amp bias and current are set and correct. The protection relay does not energize unless Pin 4 on the protection board is disconnected. The wire from pin 2 on the amp boards is very low .003 vdc. The number 4 pin on the PB is 13.35 vdc. When i connect the wire to pin 4 on the PB it releases the relay.
petehall347
the brandy coffee man
pin 4 is overcurrent detect for both channels . you need to isolate which channel the voltage is coming from .
pull this transistor on the main amp board and see if relay clicks .
DBCVette95
New Member
Thank You, I will give that a try.
Just adding to this thread since I think there is something to the incoming AC power causing this odd issue. I have an SX-980 in for service that has this same issue. After resolving some other small issues, it plays for a while, but then the relay starts cycling. It will keep trying to close for a split second, but unless I power it down for a few minutes, the relay will keep cycling. I read this whole thread and had tried most every suggestion already. But after I cleaned and tightened all of the fuse holders on the PS board, the issue definitely improved. That is about the only thing that has made any difference!
I am working in a commercial business park, where I know the AC power is poor quality. When I run it on the DBT with a 200W bulb, the receiver works fine and relay stays closed. Plugged into the wall directly, it will start cycling in and out. I am going to take the receiver home and see if that makes a difference too, but I suspect it will.
I am working in a commercial business park, where I know the AC power is poor quality. When I run it on the DBT with a 200W bulb, the receiver works fine and relay stays closed. Plugged into the wall directly, it will start cycling in and out. I am going to take the receiver home and see if that makes a difference too, but I suspect it will.