Soundstream Reference 1000SX repair

audiophyle247 · 25th May 2012, 07:29 PM

I think this is my first post here, and must say the option that pops up with search results before starting a thread is awesome. While it brought up threads I had already read after searching on my own, I think this is something all forums could use. Now back on topic..... I have a blown Ref 1000sx amp I am repairing and need to find the proper resistance for a burnt up resistor. In the thread by mike49504 there is conflicting info, talking about the R124 spot taking a 3.32ohm, or a 7.5ohm, or even a 15ohm. Just looking for clarification as to which I should use. The R124 on this board is a part of the power supply, and here are some pics for reference.

Perry Babin · 25th May 2012, 08:25 PM

It's likely 15 ohms. You can see the corresponding resistor for the other two power supply driver transistors. In the photos that I have, it's R125. It connects between the emitters of the power supply driver transistors.

audiophyle247 · 25th May 2012, 09:56 PM

Thanks Perry. The R125 is 15ohm, cool. Oddly the burnt one still reads 14.9ohm but I didnt think that was trustable. It is notably larger than R125, but the arrows & such drawn to the burnt R124 was there when I opened it so it has probably been replaced once already.

audiophyle247 · 22nd June 2012, 01:57 AM

Im back with another resistor question. I finally have the amp all back together and it seems to be working pretty good however the very large resistors (piggybacked pairs) are getting hot. After a several minutes they are reaching 200*F, while the rest of the amp barely climbs over ambient (80*F) with the highest temp found being 86*F by the time the resistors are reaching 190*F+ I dont think this is normal, can anyone verify? The color bands are all faded away, but both pairs are reading 1ohm each when tested at the board connections, and rise in temp almost equally.

1moreamp · 22nd June 2012, 05:26 AM

1 ohm 5 watt is what I have info of. They used a couple 3 watters to get the 5 watt rating in your amp. Yes they run hot to the touch in many cases to the point of color band fade. I have replaced them with sand blocks in the past without issue.
The caps attached to those resistors form a simple snubber type filter, are they in spec also? Rails on secondary should be +&- 37.8 volts DC respectively....

I see a non-original gate totem pole driver in there for Q10 and Q19. The 2SA1562 is spec'ed but its not there, the other is a simple 2N2222 metal can transistor usually also for Q20 and Q9..

hope some of this is useful...

audiophyle247 · 22nd June 2012, 10:27 PM

Yes, the Q10 & Q19's were previously replaced with "A1266" transistors, are these sufficient or is there a better part recommended?

The Q20 is the original part, and the Q9 was previously replaced with "MPSA06" transistor. Unsure if that is also a good substitute.

The voltage at the rail caps are +46.9v & -46.9v, quite a bit higher than 37.8 but could that be because my power supply is putting out 14v & not 12v? Or is the PSU drivers allowing excessive voltage (& the reason for the extra hot resistors?)

audiophyle247 · 22nd June 2012, 10:44 PM

Also forgot to add, I cannot get the link you provided to work 1moreamp.

1moreamp · 23rd June 2012, 02:30 AM

Quote:

Originally Posted by audiophyle247

Also forgot to add, I cannot get the link you provided to work 1moreamp.

Sorry the link is a smile that did not copy correctly so no info there...

I only use the original drivers so I have not had to use replacements perhaps someone could recommend a few devices. The 2N2222 can is widely available, the 2SA1562 might have replacements but as I say I still have some NOS of them here back when I stocked parts like a mad man.

The rail voltages I quoted are spec'ed in my info. What is it idle current draw from your 12 volt supply side?

audiophyle247 · 23rd June 2012, 06:10 AM

Lol, and here I thought I was really missing out on something good.

I found a thread about a Ref400 where Perry recommended a BD140 for the 2SA1562, so Im going to give them a try. (reversed mounting as their pins are backward of course)

The amp draws a hair over 2amps at the main fuse when idle, 2.09A to be specific.

1moreamp · 23rd June 2012, 04:30 PM

Hummm.. 2 amps seems a bit on the high side from what I recall for these amps. Which mosfets are being used in the power supply ?

And has there been any channel repair work done also ?

25th May 2012, 07:29 PM	#1
audiophyle247 diyAudio Member Join Date: Mar 2012	Soundstream Reference 1000SX repair I think this is my first post here, and must say the option that pops up with search results before starting a thread is awesome. While it brought up threads I had already read after searching on my own, I think this is something all forums could use. Now back on topic..... I have a blown Ref 1000sx amp I am repairing and need to find the proper resistance for a burnt up resistor. In the thread by mike49504 there is conflicting info, talking about the R124 spot taking a 3.32ohm, or a 7.5ohm, or even a 15ohm. Just looking for clarification as to which I should use. The R124 on this board is a part of the power supply, and here are some pics for reference.

25th May 2012, 08:25 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	It's likely 15 ohms. You can see the corresponding resistor for the other two power supply driver transistors. In the photos that I have, it's R125. It connects between the emitters of the power supply driver transistors. __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

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25th May 2012, 09:56 PM	#3
audiophyle247 diyAudio Member Join Date: Mar 2012	Thanks Perry. The R125 is 15ohm, cool. Oddly the burnt one still reads 14.9ohm but I didnt think that was trustable. It is notably larger than R125, but the arrows & such drawn to the burnt R124 was there when I opened it so it has probably been replaced once already.

22nd June 2012, 01:57 AM	#4
audiophyle247 diyAudio Member Join Date: Mar 2012	Im back with another resistor question. I finally have the amp all back together and it seems to be working pretty good however the very large resistors (piggybacked pairs) are getting hot. After a several minutes they are reaching 200F, while the rest of the amp barely climbs over ambient (80F) with the highest temp found being 86F by the time the resistors are reaching 190F+ I dont think this is normal, can anyone verify? The color bands are all faded away, but both pairs are reading 1ohm each when tested at the board connections, and rise in temp almost equally.

22nd June 2012, 05:26 AM	#5
1moreamp diyAudio Member Join Date: Dec 2005 Location: Northern California	1 ohm 5 watt is what I have info of. They used a couple 3 watters to get the 5 watt rating in your amp. Yes they run hot to the touch in many cases to the point of color band fade. I have replaced them with sand blocks in the past without issue. The caps attached to those resistors form a simple snubber type filter, are they in spec also? Rails on secondary should be +&- 37.8 volts DC respectively.... I see a non-original gate totem pole driver in there for Q10 and Q19. The 2SA1562 is spec'ed but its not there, the other is a simple 2N2222 metal can transistor usually also for Q20 and Q9.. hope some of this is useful...

22nd June 2012, 10:27 PM	#6
audiophyle247 diyAudio Member Join Date: Mar 2012	Yes, the Q10 & Q19's were previously replaced with "A1266" transistors, are these sufficient or is there a better part recommended? The Q20 is the original part, and the Q9 was previously replaced with "MPSA06" transistor. Unsure if that is also a good substitute. The voltage at the rail caps are +46.9v & -46.9v, quite a bit higher than 37.8 but could that be because my power supply is putting out 14v & not 12v? Or is the PSU drivers allowing excessive voltage (& the reason for the extra hot resistors?)

22nd June 2012, 10:44 PM	#7
audiophyle247 diyAudio Member Join Date: Mar 2012	Also forgot to add, I cannot get the link you provided to work 1moreamp.

23rd June 2012, 06:10 AM	#9
audiophyle247 diyAudio Member Join Date: Mar 2012	Lol, and here I thought I was really missing out on something good. I found a thread about a Ref400 where Perry recommended a BD140 for the 2SA1562, so Im going to give them a try. (reversed mounting as their pins are backward of course) The amp draws a hair over 2amps at the main fuse when idle, 2.09A to be specific.

23rd June 2012, 04:30 PM	#10
1moreamp diyAudio Member Join Date: Dec 2005 Location: Northern California	Hummm.. 2 amps seems a bit on the high side from what I recall for these amps. Which mosfets are being used in the power supply ? And has there been any channel repair work done also ?