SVT 7Pro Rebooting - Mainboard Replacement?

[Shlabotnik]

Just when I thought t couldn't happen to me...
I bought it from GC as a refurb about 4 years ago and it's worked wonderfully ever since. Until 2 days ago. It turns on and plays fine at first but starts shutting down and turning back on again every couple of minutes. Stays dormant for about 2 seconds then everything comes back to life again... Ad infinitum...

So I called support and they said it's probably the mainboard as the amp is an older serial number.

I'm going to order a new mainboard from Full Compass and replace it myself (sadly it's out of stock and I have to wait a few weeks do it) to try to save some $ and time rather than bring it to a shop. I've got a lot of experience building and repairing computers of various types so I'm fairly confident I can do it myself but I'm wondering if anyone else has ever tried this before and, if so, if you've ever run into any issues or if there are any specifics I should know about?

Thanks a lot in advance!!

 

[Shlabotnik]

I found this old post from JimmyM in another thread, so that's useful!

"Hodgy once said that anyone could replace a board in 10 minutes. Not much to it...a few screws, a couple cables with molex connectors, and you're in business."

 

[beans-on-toast]

I'd have the inside inspected, make sure that it isn't covered with dust that could be causing the problem. Also reseat all the connectors.

 

[Shlabotnik]

I'd have the inside inspected, make sure that it isn't covered with dust that could be causing the problem. Also reseat all the connectors.

It does look quite clean inside but I will reseat all the connectors and see if that helps. Thanks!!

 

[Pizza1988]

I have the same amp, same problem. I have been using a Portaflex it it's place and it just isn't the same. I would love to fix it but have no idea where to begin so I am looking forward to seeing how you solve this.

 

[Passinwind]

I'm going to order a new mainboard from Full Compass and replace it myself (sadly it's out of stock and I have to wait a few weeks do it) to try to save some $ and time rather than bring it to a shop. I've got a lot of experience building and repairing computers of various types so I'm fairly confident I can do it myself but I'm wondering if anyone else has ever tried this before and, if so, if you've ever run into any issues or if there are any specifics I should know about?

Thanks a lot in advance!!

Can we assume you at least have the bare minimum of tools to check your work? By that I mean an oscilloscope, signal generator, DMM, properly rated dummy load, and preferably a Variac with an isolation transformer. And if you have that stuff, have you already confirmed that "probably" diagnosis you got on the phone?

 

[Shlabotnik]

I have the same amp, same problem. I have been using a Portaflex it it's place and it just isn't the same. I would love to fix it but have no idea where to begin so I am looking forward to seeing how you solve this.

I will be sure to update you on my journey!!

 

[Shlabotnik]

Can we assume you at least have the bare minimum of tools to check your work? By that I mean an oscilloscope, signal generator, DMM, properly rated dummy load, and preferably a Variac with an isolation transformer. And if you have that stuff, have you already confirmed that "probably" diagnosis you got on the phone?

I'm afraid not. I'm just figuring that, given all of the other issues people had with this amp model, that it is the mainboard problem that they also had. I also figure that it would be a lot cheaper to replace a $180 board than to pay someone for the hours of labor it might take to diagnose the actual problem with the board. It's a gamble for sure.

 

[Passinwind]

I'm afraid not. I'm just figuring that, given all of the other issues people had with this amp model, that it is the mainboard problem that they also had. I also figure that it would be a lot cheaper to replace a $180 board than to pay someone for the hours of labor it might take to diagnose the actual problem with the board. It's a gamble for sure.

In the long term it just might be cheaper to at least have a qualified tech with the right tools do a thorough bench test once you've replaced that board. It's a very powerful amp and the answers to what could go wrong are not all that pretty.

 

[agedhorse]

I'm afraid not. I'm just figuring that, given all of the other issues people had with this amp model, that it is the mainboard problem that they also had. I also figure that it would be a lot cheaper to replace a $180 board than to pay someone for the hours of labor it might take to diagnose the actual problem with the board. It's a gamble for sure.

Wouldn't it be a shame if after replacing the board you continued to have the same problem? This is what Charlie is getting at with proper diagnosis.

What speakers are you using with your amp?

 

[Shlabotnik]

Wouldn't it be a shame if after replacing the board you continued to have the same problem? This is what Charlie is getting at with proper diagnosis.

What speakers are you using with your amp?

It sure would!

This particular model is quite well known to have problems with the mainboard, specifically the earlier serial numbered models like mine. That is why I'm assuming it is the board. It's not a complete shot in the dark. But yes it would be lousy if that were the case.

I am running it through 2 8-Ohm Eden cabs, a D-210T and a D-115T.

 

[beans-on-toast]

Have you always used that speaker combination?

Have you tried it with just one cab connected?

Are the speakers daisy chained?

What sort of cableing is running from the amp to the speaker, speakon or ¼"?

 

[Shlabotnik]

Have you always used that speaker combination?

Have you tried it with just one cab connected?

Are the speakers daisy chained?

What sort of cableing is running from the amp to the speaker, speakon or ¼"?

Have you always used that speaker combination?
Yep!

Have you tried it with just one cab connected?
No but I've tried it with zero cabs connected and it shuts off and turns on again in the exact same manner.

Are the speakers daisy chained?
No.

What sort of cableing is running from the amp to the speaker, speakon or ¼"?
1/4"

 

[beans-on-toast]

Have you always used that speaker combination?
Yep!

Have you tried it with just one cab connected?
No but I've tried it with zero cabs connected and it shuts off and turns on again in the exact same manner.

Are the speakers daisy chained?
No.

What sort of cableing is running from the amp to the speaker, speakon or ¼"?
1/4"

Having the same issue, with or without a cab connected eliminates some issues. More than likely, back to a problem with the main board.

 

[BassmanPaul]

You should also switch to SpeakOn connectors on your speaker cables. That amp is way too powerful to work safely with 1/4" Phone jacks.

 

[steelbed45]

I had the same issue, but with my case, it was because it was a Rev. D board with what support called an underspec'd ICE chip. It had the 2A165, not the 2A265. Totally random when that amp would shut down, but when it did, it was game over for the night. I hope you can find a solution that works for you, I loved the sound of the 7-Pro.

 

[Shlabotnik]

I had the same issue, but with my case, it was because it was a Rev. D board with what support called an underspec'd ICE chip. It had the 2A165, not the 2A265. Totally random when that amp would shut down, but when it did, it was game over for the night. I hope you can find a solution that works for you, I loved the sound of the 7-Pro.

Wow! Yes, I do love it. And it's worked great for me for years now. I'm hoping (assuming?) that the new board they send me would have all of these issues ironed out by now, given that it's something they've been aware of for some time. But we shall see... I will report back when it comes in!

 

[seamonkey]

Did you pull the tube?
Did you try to disconnect the pre-amp?

It might help isolate an over current that could cause the power supply to shutdown

 

[JimmyM]

There is a chip inside of it that's usually the culprit. ICE2A165 needs swapped to an ICE2A265. If you can solder to PCB's or know someone who can, you can change it out for a few bucks and see if it works again. I have known people to rescue theirs by changing just the chip. Otherwise, the motherboard's a matter of a few molex plugs and a whole bunch of screws. Just take pictures of all the connections and you're good. And while agedhorse is always correct about spending good money after bad, this is a known problem with the 7 Pro till the new chip came out in 2014, it's a cheap fix if it works, and if you screw it up, the worst that happens is you buy a new motherboard.

Link Removed

 

[Hand slap]

Just when I thought t couldn't happen to me...
I bought it from GC as a refurb about 4 years ago and it's worked wonderfully ever since. Until 2 days ago. It turns on and plays fine at first but starts shutting down and turning back on again every couple of minutes. Stays dormant for about 2 seconds then everything comes back to life again... Ad infinitum...

So I called support and they said it's probably the mainboard as the amp is an older serial number.

I'm going to order a new mainboard from Full Compass and replace it myself (sadly it's out of stock and I have to wait a few weeks do it) to try to save some $ and time rather than bring it to a shop. I've got a lot of experience building and repairing computers of various types so I'm fairly confident I can do it myself but I'm wondering if anyone else has ever tried this before and, if so, if you've ever run into any issues or if there are any specifics I should know about?

Thanks a lot in advance!!

I was a Ampeg service Cntr, years ago, and have worked on, and owned that model, the main board consist of the power supply, amp, and the system control circuit, which is fairly high tech, AND yes, it's plug & play, pretty straight forward, unless there are changes in versions, different connectors, probably unlikely. Out of all the Class D amps, I have owned, and worked on, the SVT Pro is one of the most impressive, "to me" with the power amp components used, pretty robust looking, I guess they have had issues though, hopefully new boards are problem free.