TC Electronics voice solo XT SMD diode problem

[blindboybenton]

Good morning /Afternoon to you all

I have an issue with a Active monitor, Came in for strange sounds, I tracked it down to the Output chip STA5150 ( I think) while testing it a couple of SMD diodes went up in smoke

I have 815 on it. In fact there is a UN with a circle round it and then 815 and LT. I cant find any info on this diode
Does anyone have any charts or info on it or any other diode that may do the job, TC Electronics don't give out maps
Picture below


The repair is still cost effective at this stage

BBB

[Mick Bailey]

Try here:

SMD CODE - Electronic semiconductor smd code, smd database, smd code book,

Also double-check it isn't 81S

[blindboybenton]

Thanks mick

Ive checked again im sure it is 815 ive checked 81s too. the link shows a 815 it as a 1SMA5915B on RS its a 3.9v zener http://uk.rs-online.com/web/p/zener-diodes/8008958/
81s comes up with " Linear voltage regulator integrated circuit " and one zener diode as a 3 pin sot
Pain in the arese without a map
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[blindboybenton]

Thanks mick

Ive checked again im sure it is 815 ive checked 81s too. the link shows a 815 it as a 1SMA5915B on RS its a 3.9v zener 1SMA5915BT3G | ON Semiconductor 1SMA5915BT3G Zener Diode, 3.9V 5% 1.5 W SMT 2-pin SMA | ON Semiconductor
81s comes up with " Linear voltage regulator integrated circuit " and one zener diode as a 3 pin sot
Pain in the arese without a map
BBB

[Mick Bailey]

The only other reference I found to 815 is this, though they give the marking as 815B. That B could make all the difference, though. TC won't even give you the time of day.

datasheet.pdf

[olddawg]

Have you tried this?
Support | TC Electronic
If you can't get a manual, usually a tech monitors the user forum. Also Sweetwater sells TC. Call their customer support and ask where you can get a schematic. Tell both companies there will be no TC products in your future and that you will advise everyone you know for the rest of your life not to either unless they help you. Squeaky wheel and all that! They don't like that kind of press. They might even fix it for shipping cost free. Even without a receipt. Say it was a gift.

[Mick Bailey]

See this for their approach; http://music-electronics-forum.com/t39056/

[blindboybenton]

well ive fitted the new output chip and 2 x 3.9v smd diodes 1SMA5915B. turned on with a lamp limiter (not drawing any excessive current and smoke again from diodes and both s/c now
as i aint got a map ive had a look at some sta5150 circuits and i can't find any with any sort of Zener diodes

anybody any thoughts apart from dumping the feckin thing. Im going to list this amp to the ones i wont touch again, already have another tc electronics in there, and any hifi amp with HDMI

BBB

[olddawg]

I would not be working on any modern solid state equipment with a lightbulb limiter. It's ok for simple old robust stuff, that's what TV techs did it the 1970s. If you do a lot of modern audio, you need an isolated bench variac with a current meter. You won't eat up output devices that way. Did you try the TC Forum? Are you sure the board has not become conductive under the component. Many cheap boards are nothing more than resin impregnated paper. When an SMD component "smokes" it can charcoal the board, effectively making a resistor under it.

Also.. What makes you sure it's a diode? Are you sure it isn't a fusesistor, a low value resistor on the rail or something? Are there good components on the board with the same designation that have verified it's a diode? I would use the pin out from the data sheet for the output IC and do a lot of static measurements on the board with the IC removed.

[olddawg]

Also... Did you turn it on with the speaker connected? In most cases you never turn an SS amp on after an output failure with the speaker connected. You check for DC offset first. What this looks like to me: If those are really are zeners they are probably reference for symmetrical regulators and you need to check the associated transistors and peripheral components. If they are fusistors or 10 ohm, 100 ohm, whatever.....You may have had a simple catastrophic failure of the output IC and all you needed to do is replace it and a couple of fusistors. Putting in the zeners may have damaged the new IC and /or something else. Maybe not. I would disconnect the speaker load, fire it up, and take some voltage measurements on the IC. You may have it fixed except for a couple of 10 ohm resistors if the zeners caused no mischief. I seem to remember that number. May be 1.5 amp fuses. I had a Roland the other day that had been in 3 shops. It had 2 bad SMD 2 amp fuses and a bad output IC. They had no schematic and did not recognize the SMD packages as fuses.

[blindboybenton]

Hi

These two components are 100% diodes Board has the usual marking for diode. Speaker was not connected when i turned on. Marking on the diode was 815
Im going to spend another hour on this before i box up and return. Not easy to work on
Hate TC electronics stuff, Just too busy

BBB

[blindboybenton]

Screwed it all up and handing it back, cut my looses customer will pay a handling charge and that should about cover the parts


Thanks for the help

BBB