"BLISTERED"! Orange Micro Terror output repair.

[@flakeyjake4177]

Bwahahaha you crack me up, dude......cuz you STILL be "en-ga-neerin'"!!! I hope you and the family are all doing well!!!! I'm nine months into retirement and loving it. Should be getting my first SS check this month! Thanks for this chance to "see" you. Hopefully you're enjoying being retired as much as I am.

[@leonardpeters3266]

I like it allot more than going to work. Hope you and yours are doing well to Liz.

[@VanXHydrA]

Like how much and where can you get these replacement chips? And also, are there other types and perhaps slightly different tone wise sounding ones if these “output chips”? I hope they are extremly cheap if that’s what burned out in my with the tiny amount of playing through mine I actually did Ina lil over a year before it started sputtering like a bad I o it Jack or cable then shit out on me entirely one day!

[@leonardpeters3266]

This is where I got mine. They are about 5 bucks. I ordered 2 just in case. www.digikey.com/en/products/detail/stmicroelectronics/STA540/2063213 As for the second question I wouldn't advise using a different output chip. But if you want to mess with tone, the tube in the amp is a great place to go. Trying different ECC83/12AX7 tubes. I believe there is a KZbin video of the differences.

[@aaci0r]

Hi. I have found chip that I also need to replace but have one question. It must be 20W chip or it can be 30 or 33 W? Higher audio power might occur some other problems? Or this electrical system can handle this power? Or maybe original chip have more wattage than whole amp? Cheers.

[@leonardpeters3266]

The STA540 is actually 2x 34 W into 8 Ω at 22 V, 1 kHz, 10% THD. Or 2x 15 W into 8 Ω at 16 V, 1 kHz, 10% THD. It is my belief that they chose to run it in between with a large heatsink to maximize the life of the chip and minimize failures. Several parameters would need to be analyzed if modification were intended, not the least of which would be power supply capability. I think I would stick with the original design.

[@jonathanmartin3375]

I have a Micro Terror that turns on and works through the headphone jack, but not through the output jack. Do you think this chip would cause that?

[@leonardpeters3266]

It is definitely possible, the headphone jack is run off of the op amp before the power chip. It could also be because of the 10uf capacitor that feeds the signal to pins 4,5 of the power chip.

[@jonathanmartin3375]

@@leonardpeters3266 Thank you so much for the reply and info. I've ordered the new chip and will let you know what happens once I've installed it! If that doesn't fix it, I'll check out the 10uF cap next.

[@jonathanmartin3375]

I replaced the STA540 and it's still behaving the same way. I'm thinking my next step is to check if I get voltage into the VCC1 pin 3?

[@leonardpeters3266]

@@jonathanmartin3375 Jonathan, I can't be there unfortunately, but I can send a shortcut to the schematic: github.com/d3vCr0w/orange_terror_schematics/blob/main/Orange%20Micro%20Terror.pdf There are 2 interesting things. One is the 10uf cap that goes between pin 1 of U3A and the input of the STA 540 (pin4-5). But another interesting thing is a transistor Q2 that puts the STA540 (pin7) into standby mode when the headphones are plugged in. It does this when the ground on the jack side of R38 is lifted. In other words when the jack side of R38 is grounded, STA540 is not in standby. I would want to measure voltage (U4-7) at the collector of Q2 and make sure it changes when you plug and unplug your headphones.

[@leonardpeters3266]

When the headphones are unplugged the voltage at the base of Q2 should be near 0 (about .23v) and the voltage at the collector (U4-7) should go high, taking pin7 of the STA540 out of standby. When the headphones are plugged in, the voltage at the base of Q2 should go higher and the voltage at the collector (U4-7) should go lower putting pin7 of the STA540 into standby.

[@1-derfulpiece]

Is it safe to touch and work on this pedal? Do I have to work about getting shocked like a regular amp?

[@leonardpeters3266]

I believe it runs on 15 volts 2 amps. I still suggest not getting in the habit of putting your fingers inside powered electronics. But these are more benign then most.

[@1-derfulpiece]

did you have to have to take the voltage out of the caps? @@leonardpeters3266

[@nordodin5815]

I had got the one. I sold it after 1 year using. As for me, it gives extremely bad sound, it's impossible to use effects with it🤷‍♂️

[@patrickcarr9428]

Where's da flux?

[@leonardpeters3266]

In the solder core. How have you been?