Is it over? 21NYC Sansamp Bass DI

[Jimijames31]

The bass player in my band fried his Sansamp pedal here. I have dis-assembled it to check it out and cleaned out the fried parts. I contacted Tech21 to get the replacment resistors and diodes, the engineer gave me a slightly cryptic response but I think I can sort it out.

After a little more work on cleaning up the board today I am thinking that it is too burned up to repair.

Opinions?

[glebert]

If you can trace where those components connect to and can solder to a non-burned area that might work better than trying to reuse this location. I don't like how narrow Tech 21 goes with their PCB routes, they are fragile. It's not like they are saving money on copper or anything. Dealing with Tech21 for repair support is interesting. I talked with the engineer for like an hour when I was fixing a Trademark 60 last year (about the amp and then just shooting the breeze). If he could have send me a schematic, or even a screen shot of the section of the schematic or board layout it would have been much easier, but I got the fix done and everyone was happy.

[Chuck H]

Second that on either moving the location or at least elevating off the board and flying leads to good contacts. I'd even suggest cutting through any traces going into the burned area. With that much carbon on and in the board the possibility of some conductivity between traces could foul circuit operation.

[Jimijames31]

I'll try to track down some other areas to solder in to. That was my first experience with tech 21. I agree would be great to either see a snapshot of the area on the board or a schematic. I guess I'll do my best and see if I can get her running again. On the plus side my bass player bought a newer version of the pedal so this is just for fun. Thanks for the advice.

[Jimijames31]

Thanks Chuck, I appreciate the advice. I am pretty green with this stuff.

[Tom Phillips]

...I am pretty green with this stuff.

Hi James,
A word of caution...In a situation like you have, in addition to replacing burnt up parts, you will need to troubleshoot the circuit and determine what fault caused those parts to burn up. Otherwise, you could complete a really nice cosmetic repair and then have the same parts burn up again.
Cheers,
Tom

[nosaj]

Hi James,
A word of caution...In a situation like you have, in addition to replacing burnt up parts, you will need to troubleshoot the circuit and determine what fault caused those parts to burn up. Otherwise, you could complete a really nice cosmetic repair and then have the same parts burn up again.
Cheers,
Tom

A larger pic of the circuit board being that those were diodes(maybe protection diodes) maybe blown from wrong power adapter or polarity?
Just speculating cause you don't typically get the power source as the offender realizes what they did and just can't admit it.

Give us some larger better pics of the PCB Thanks,
nosaj

[Chuck H]

I was thinking the same thing. Isn't the Sansamp a preamp device? I can't imagine that sort of incineration occurred due to currents present in the Sansamp then. User must have done something odd. Like plug a power amp into it? Even then I would expect any reasonably high input impedance to avoid this sort of thing. A mystery to be sure, but my guess is that someone did that device some dirt somehow.

EDIT: BTW... You can buy a new one of those for under $150 almost anywhere! By the time the board/circuit is reasoned out, the parts identified and ordered and the retrofit repair accomplished this doesn't even seem like a pleasant DIY repair and CERTAINLY not financially beneficial. I'd throw that thing off a bridge and buy a new one with a warranty.

[Jimijames31]

You all bring up some great points. Our band actually already bought the bass player a new one. He had this one for 12 years. I told him we need to sort out what caused the problem though. I have never seen anything burned up this bad. I haven't had a chance to sort out his power supplies yet. The thing was intermitently screeching for weeks before it went out completely.

I am attempting to repair it more for my own education and because I like doing this kind of stuff. I figure if I can get it back together we can use it as a backup.

here's the parts list the engineer at 21tech gave me. Parts are:
D1 and D12 = 4148
D15 = 10V Zener Diode
R109 and R54 = 68 Ohms

My biggest challenge is working with no schematic and I can only find glimpses of the area in online pictures. I went as far as to contact someone who worked on one in another forum back in 2008 but he doesn't have any other pictures.

I'll take some more pics and post them later so you guys can see the whole board.

[Chuck H]

If the unit the bass player has now is the same you have a reference right there. And I can get behind doing something like this to "stay out of trouble" as it were. I have a dozen of those around. And I get your frustration with trying to glean information from on line pics (HRMPH!)

[Jimijames31]

His is a new model and as it happens, getting to that side of the board is a freakin nightmare. I had to use a solder wick and remove the input jack just to get the board out. I really should have removed the input and both output jacks but I managed to the pcb out with only removing one.

[Jimijames31]

A couple more pics of the board. Plus one before I took out the fried parts.

[J M Fahey]

Even without actually tracing the schematic, follow the tracks from burnt areas towards some "external access" point.
Nothing inside the pedal has enough voltage/current/power , Death must have come from outside.

Either from improper or failing external Power Supply / wall wart, or some Bass Head speaker out which was conneced to input or output.

Supply inputs often have protective diodes to avoid backwards voltage or AC ; jacks often have a couple diodes connected to +9V or ground, and some resistor in series to limit current; we have both in the casualty list.

So please check where tracks lead to, they won´t go "anywhere" at random but basically to one of these 2 points.

[Jimijames31]

Good advice, I'll check trace those and see where they lead. I suspect faulty external power supply. However, I wasn't actually there the night it happened and not all my band mates are very savvy when it comes to their gear. In this particular situation my buddy is using a power supply with little leap frog splitters between pedals. I told him we are getting him a pedal power source asap. I would hate for him to burn up the new pedal he just bought.

[musicheals11]

please someone help me remove the circuit board from the sansamp paradriver

The bass player in my band fried his Sansamp pedal here. I have dis-assembled it to check it out and cleaned out the fried parts. I contacted Tech21 to get the replacment resistors and diodes, the engineer gave me a slightly cryptic response but I think I can sort it out.

After a little more work on cleaning up the board today I am thinking that it is too burned up to repair.

Opinions?

[ATTACH=CONFIG]46411[/ATTACH]

i have been trying to remove the circuit board but can't figure it out, i took off all of the screws and bolts, i got the bottom off of the circuit board which was very easy, but can't get it off of the top of the pedal box. i'm also wondering how to assemble it, will it be easy or a nightmare?