Greetings,
I have a Rubicon 604 that just started acting up, I was going down the road and nothing of note special happened but I noticed the amp was cutting in and out ans suspected my battery or alternator. I got home and checked the battery and alternator and they were working nominally. I pulled the amp and in checking the main fuses they were blown, looking inside revealed C 158 as well as R298 R265 and C175 are damaged and appear related to the power supply side of the board. Does anyone have a schematic for this amp or have someone they trust to have it repaired? I have a good bit of general electronics knowledge but I'm no engineer and my access to a scope is limited.
Thanks for reading,
Fred
I have a Rubicon 604 that just started acting up, I was going down the road and nothing of note special happened but I noticed the amp was cutting in and out ans suspected my battery or alternator. I got home and checked the battery and alternator and they were working nominally. I pulled the amp and in checking the main fuses they were blown, looking inside revealed C 158 as well as R298 R265 and C175 are damaged and appear related to the power supply side of the board. Does anyone have a schematic for this amp or have someone they trust to have it repaired? I have a good bit of general electronics knowledge but I'm no engineer and my access to a scope is limited.
Thanks for reading,
Fred
Last edited:
C158 = 0.22 ufd 100 Volt < One cap of a dual RC network across one of the primary windings a simple noise filter >
C175 = 6.8 nano-farad PE 5% < LM 3524 timing capacitor >
R265 = 100 ohm 2 watt < LM3524 related current limiter>
R298 = 110 ohm 2 watt < ground current limit resistor connects three different grounds together>
Most of these items will NOT cause the amp to cut out, and if you test these devices with a ohmmeter I am thinking they will read within tolerance in most cases.
This is a SoundStream amp so the main issues likely to cause the amp to cut out are the switches, and bad solder joints on the FEB upright driver cards.
Are all four channels cutting out??? or just one ???
C175 = 6.8 nano-farad PE 5% < LM 3524 timing capacitor >
R265 = 100 ohm 2 watt < LM3524 related current limiter>
R298 = 110 ohm 2 watt < ground current limit resistor connects three different grounds together>
Most of these items will NOT cause the amp to cut out, and if you test these devices with a ohmmeter I am thinking they will read within tolerance in most cases.
This is a SoundStream amp so the main issues likely to cause the amp to cut out are the switches, and bad solder joints on the FEB upright driver cards.
Are all four channels cutting out??? or just one ???
The output was dropping out with no real rhyme or reason, I tested it on my bench and it won't output any audio now. When it turns on and should be passing audio it just pops the speakers. I don't know if this is the beginning of DC out but I noticed the board around R265 and R298 is showing signs of excessive heat and C158 has extended it's guts out the top of the casing. C175 looks like it was damaged by the heat around the 2w resistors. It's all 4 channels no matter the load or configuration. I was testing with a 12v 80a power supply and known good 8ohm speakers. Do I throw in the towel and send it off to get fixed or get the parts and hope for the best? I'm good with soldering I'm just a bit rusty on circuit level troubleshooting.
Thanks,
Fred
Thanks,
Fred
Very true. Bad driver board solderings can also cause damage I believe, besides sound cutting in and out. Not 100% sure though.
Of all the Soundstreams I disassemble I refresh these solderings.
Bad switches can usually be cured with contact spray cleaner. I'd say the worst switches are the 2.0 / 5.0 volt gain switches which can only be found on Reference s / sx models, not Rubicons. The quality of the solderings on Rubicons generally is better than on most Refs, though certain s / sx have pretty good solderings I must say.
Damage in the power supply section sometimes is related to failing rectifiers.
I have the schematics.
PM me with your email address and take some pics of the board, please.
I purchased a malfunctioning 604 recently, don't yet know what the problem is haven't looked at it yet, just opened to see whether the board was not burnt. Luckily, it isn't.
I'd interested in some pics of your board, to see the damage but also to compare with mine, I noticed some parts on my board which I don't believe should be there, if I remember correctly from a previous 604 I sold.
If C158 had exploded then it should be replaced. The other devices all show heat stress due to normal use and as long as they are within value tolerance and there solder joints are still good < a retouch should help some > I would leave them till we find out what else is wrong to cause all four channels to fail output.
The dual rectifier diodes under the board are another common failure. There are 3 each FEP16DT and 3 each FEN16DT these should be ohm'ed out to make sure they have not failed. Also check L101 to make sure it has not shorted on itself. And verify the bipolar 15 volt rails are functional at U112 and U113.
No speakers or RCAs should be connected while doing all this diagnostic, just power and if possible measure the idle current draw of the amp from its 12 volt supply. Sometimes this can indicate if something is shorted on itself inside the amp.
Popping speakers and no music could be one of the rail supplies has failed but you will need to measure some voltages for me of the main rails, lower 15 rails and the DC output of each channel. Schematics will be helpful if you know how to read them, and or need to know a value of some damaged component. So take AZVRT up on his offer IMO...
The dual rectifier diodes under the board are another common failure. There are 3 each FEP16DT and 3 each FEN16DT these should be ohm'ed out to make sure they have not failed. Also check L101 to make sure it has not shorted on itself. And verify the bipolar 15 volt rails are functional at U112 and U113.
No speakers or RCAs should be connected while doing all this diagnostic, just power and if possible measure the idle current draw of the amp from its 12 volt supply. Sometimes this can indicate if something is shorted on itself inside the amp.
Popping speakers and no music could be one of the rail supplies has failed but you will need to measure some voltages for me of the main rails, lower 15 rails and the DC output of each channel. Schematics will be helpful if you know how to read them, and or need to know a value of some damaged component. So take AZVRT up on his offer IMO...
Yes, do the joints even if they look good. Add just a little bit of solder and make sure you don't create bridges between non-connected solders.
Get some contact cleaner spray for the switches. Spray them and work them back and forth many times.
And like 1moreamp suggested, do an ohms-test on the rectifiers.
These 3 are the most common problems with Soundstream amps of that era and should be checked first.
Get some contact cleaner spray for the switches. Spray them and work them back and forth many times.
And like 1moreamp suggested, do an ohms-test on the rectifiers.
These 3 are the most common problems with Soundstream amps of that era and should be checked first.
Here are pics of the board, not the best but will get the idea across as to what I'm seeing. I will get my meter from work tomorrow and be able to test the items 1moreamp suggested and will report back. Thanks for your thoughts and knowledge on this, gotta love the internet!
Regards,
Fred
Regards,
Fred
Attachments
C158 is bad and needs to be replaced.
R298 110 ohm 2 watt appears to have burned up and there is board damage that will need to be repaired and the two caps near it are also cooked by the looks of it.
Caps C178 and C190 are both 0.1 ufd caps.
All of these components connect the three different grounds of the amp together. So something else is wrong that caused all of this. please check your DC output from each channel once you can get the amp to turn on again and let me know what you find at the speaker terminals
R298 110 ohm 2 watt appears to have burned up and there is board damage that will need to be repaired and the two caps near it are also cooked by the looks of it.
Caps C178 and C190 are both 0.1 ufd caps.
All of these components connect the three different grounds of the amp together. So something else is wrong that caused all of this. please check your DC output from each channel once you can get the amp to turn on again and let me know what you find at the speaker terminals
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.