iFixit - Answers With Device "Musical Instrument Accessories"

Fender Frontman 15r: have frontman 15g.is power switch my problem?

Thu, 29 Dec 2016 04:44:16 -0700

bought used from thrift store. Looks new,but when I turn it on it hums even with all of the dials turned down. And if I plug in my cord it starts popping.I don't know whats wrong exactly.I'm thinking power switch?

⟐ Answered dicembre 29, 2016 at 4:44 GMT-7

Behringer U-Phoria UMC204HD: I need someone to identify this circuit board component.

Thu, 08 Jan 2026 12:09:27 -0700

I'm repairing a Behringer U-Phoria UMC404HD. There was a tiny component that received both the signals of USB data(+) and data(-), before allowing both to proceed towards the XMOS chip. Please take a look at the image above to check out how the component (with arrows pointing at it) and the surrounding area looks in an undamaged UMC404HD.

There has been an attempt, by the former owner, to repair the USB connections, which left this particular component destroyed.

Could someone tell me what is this component and, if possible, the specs it might have, so I can order a suitable replacement?

I don't have much knowledge in parts names and uses, but I can do a good job, when it comes to repairing circuit boards.

⟐ Answered gennaio 08, 2026 at 12:09 GMT-7

Peavey VK100: Guitar Amp not turning on...

Sun, 27 Sep 2020 04:26:48 -0700

Peavey Valve King 100 doesn't seem to be getting power...no power light or any kind/type of sound. Have checked power cord even tried different ones. Have checked electrical outlet, even tried different ones.

Amp got turned over while playing, but wasn't dropped. It did break input jack, but was still able to play through it.

It started blowing outside fuse beside power jack on back where electrical cord plugs in. Took all of tubes out and systematically replaced one at a time until found the one blowing fuse. Amp worked for a while at home, but when I took amp out to friends house to practice with band, it just died...stopped all together, and wouldn't power up any more.

Can't afford new amp so advice to fix it will be deeply appreciated.

Thanks,

Keith

⟐ Commented settembre 27, 2020 at 4:26 GMT-7

Guitar Amplifier: Looking for parts to Vox Valvetronix VT20X

Sun, 10 Jan 2021 12:14:59 -0700

So a drunken friend of a friend fell on my Vox Amp and broke off the power supply at the amp. Its a small chip labeled "KLM-3507". I've managed to trace down that this is a KORG manufactured PCB. The issue I am having is finding anyone locally who works on amps that can help me track down a place to order this part.

Hoping someone out there may be smart enough on VOX or KORG amps to let me know either where to order this part from, or if I am missing something about the part number and there is another chip I should order. Final option, if someone knows a good way to jerry rig a new and possibly more robust power supply that would also be more advisable than my current "make it a coffee table" option.

⟐ Answer edited gennaio 10, 2021 at 12:14 GMT-7

Fender Frontman 15r: I have a broke 1/4 inch input jack

Wed, 11 May 2016 09:05:04 -0700

My son accidentally turned amp over & broke the input jack. where can I get a input jack& is this a hard fix?

⟐ Answered maggio 11, 2016 at 9:05 GMT-7

Fender Frontman 15r: Channel switching button seems to be having poor contact/broken.

Sun, 04 Aug 2024 15:59:05 -0700

When attempting to switch to the drive channel on my amp, the button seems to be having a contact issue. When I press it to use the drive, the sound doesn't come out, or when it does it sounds like when a cable is having contact issues. I know the issue is on the button itself because sometimes when I press it on a specific way, the drive channel works without issues, but after playing a while, I assume the vibrations move the button out of the good position because it goes back to the same issues as before. What's the best way to fix that? Should it need replacement, how do I go about looking for a new one? Replacement parts for amps seems hard to find.

⟐ Answer accepted agosto 04, 2024 at 15:59 GMT-7

Guitar Amplifier: Crate GFX 212T amp sound cuts out

Tue, 09 Jul 2024 09:11:41 -0700

The sound cuts out on my Crate GFX 212t but returns with pressure on any control knob or bumping the amp. I'm thinking loose solder joint but not sure where to start.

⟐ Commented luglio 09, 2024 at 9:11 GMT-7

Fender 65 Twin Reverb: Need Help Replacing a 240v Mains Transformer - RESOLVED

Sun, 14 Jan 2024 01:15:53 -0700

So I need to replace the mains transformer in this amp. It is a 240V primary power. The new transformer wire colours do not match the schematic I have and I am having difficulty identifying which wires on the primary side go where. I have the secondary side nutted out. Appreciate some help with the primary side. Cheers.

Pictures attached

Hey guys - I contacted Hammond - the maker of the transformers, and he gave me an updated wiring diagram. This coupled with a mate working out which primary wires go to which jumper sorted the problem and the amp and its new transformer are on speaking terms. Big thank you to all who contributed to this thread. Cheers, Rhea deLascy-Wells.

⟐ Edited gennaio 14, 2024 at 1:15 GMT-7

Guitar Amplifier: knobs crackle and pop

Wed, 23 Feb 2022 11:39:01 -0700

old peavy amp.. knobs crackle and pop

⟐ Comment deleted febbraio 23, 2022 at 11:39 GMT-7

Guitar Amplifier: Change xlr speaker outs to 1/4" speaker outs?

Fri, 01 Jun 2018 07:21:01 -0700

This vibration technologies sl140 is a solid state slave amp. There are two xlr (microphone) cable speaker outs that I want to switch to 1/4" jacks.

The 1/4" jacks have three pins on the back.

The xlr jacks are also connected by three wires to the circuit board.

The xlr jacks also come out of the amp as 8 ohm and 16 ohm and are wired accordingly within(3 wires).

I understand I only need two wires (+ and -) to wire up the 1/4" jacks and I'm handy with a voltmeter to determine what pins are center or not but the xlrs and internal wiring of the amp are throwing me.

My thoughts are two of the wires are the same (either hot or ground) and the lone wire will be the other. Determining which is hot or ground in the amp is a problem.

The wires are colored and I am planning on opening up to see the board and what's what but was kind of hoping for someone who may know a thing or two to throw a bone my way. I was hoping it would be quite easy to do.

(Couldn't find a schematic, info or an active number for this company.)

Thanks

⟐ Answer accepted giugno 01, 2018 at 7:21 GMT-7

Behringer U-Phoria UMC204HD: My interface doesn't wanna connect on my computer

Wed, 13 Nov 2024 20:50:08 -0700

Interface program

⟐ Commented novembre 13, 2024 at 20:50 GMT-7

Guitar Amplifier: Loud noise only when input in

Wed, 18 Sep 2024 11:48:36 -0700

New to these devices (this is a Peavey Vypyr VIP 2) and I have no idea what is causing it. I see multiple things that look wrong but nothing I can definitely say is causing the issue and it honestly looks like someone else opened it and did stuff before me. Any ideas are appreciated.

Edit: new issue, whining with no volume on, loud noise when volume on. New better pictures and new video

Edit:

⟐ Commented settembre 18, 2024 at 11:48 GMT-7

Fender 65 Twin Reverb: Dead Normal Channel - No Sound at All.

Thu, 25 Jan 2024 21:06:21 -0700

Hi - yes its the same amp which had the transformer issue. This time, in spite of the new transformer, the normal channel is silent. No sound when I plug guitar in. Here is what I have done so far. Aside from the transformer, I have also replaced, the filter caps, all tubes, retensioned the tube seats, cleaned seats, pots and jacks. The only sound I will get is when I run the guitar lead across my hand. Note, the guitar and lead works perfectly on the vibrato/reverb channel. What have I missed?

⟐ Commented gennaio 25, 2024 at 21:06 GMT-7

Fender 65 Twin Reverb: Dead Channel on Fender Twin

Sat, 13 Jan 2024 23:51:47 -0700

Fender Twin Reverb (re-issue) clean (or normal) channel not working. All tubes have been replaced - to no avail….what do I check or need to repair/replace?

⟐ Commented gennaio 13, 2024 at 23:51 GMT-7

Fender Champion 600: Side black chassis screws

Fri, 11 Nov 2022 02:08:03 -0700

I bought this amp with only one side chassis screw (black one on the picture attached).

I’ve been searching all over the internet trying to find one available for purchase but failed to find any. Also I don’t have anything to measure the thread, so can’t find an alternative. If any of you guys know where to find one of those screws or anything similar - I’d greatly appreciate it 🙏🏻

⟐ Commented novembre 11, 2022 at 2:08 GMT-7

Marshall MS-2: Micro Amp Battery power not working.

Sat, 07 Dec 2019 11:11:23 -0700

My MS-2R micro amp by Marshall has never failed me in the past but I recently noticed that when I try to use battery power it doesn't work. The wall input works and sounds fine but the battery power doesn't work. I have replaced and used at least 3 different batteries but still no solution.

please help, have a nice day

⟐ Commented dicembre 07, 2019 at 11:11 GMT-7

IO DOCK II: How can I solder direct current whit the original charger?

Thu, 16 May 2019 08:14:23 -0700

I have a alesis iO Dock 2 , and the power plug in broke and i lost the little piece but it was working ok, so im trying to plug ( solder) the charger direct to the pcb but it does not say which one is positive or negative anybody can help me? Or is there a tutorial about finding the positive and negative on a pcb board whit no electricity runing?

In advance thanks.

⟐ Answer edited maggio 16, 2019 at 8:14 GMT-7

Guitar Amplifier: no power on fender princeton 112 plus

Mon, 26 Feb 2018 19:04:45 -0700

I turned on my amp and no power. Have checked on/off switch, (good), capacitor, no power coming out. (Basler BE 2526901, PO 29668; 695-9801; no longer listed on company parts charts).

Does anyone know a replacement part for this part? Amp selling in my area is going for $130.00 or so. Is it worth trying to fix?

Thanx

⟐ Answer edited febbraio 26, 2018 at 19:04 GMT-7

Alesis SR-16: How do I diagnose this motherboard?

Sun, 03 Aug 2025 04:40:47 -0700

Hi, I would like to repair this Alesis SR-16. I powers on but there is only a slight display output, the LCD somewhat illuminates but it does not display any characters. When I plugged it in for the first time, it displayed some gibberish however. There is also no sound output.

I do not have any experience with repairing a motherboard like this and would there appreciate your help.

⟐ Commented agosto 03, 2025 at 4:40 GMT-7

teenage engineering ob-4: May I know if I can buy an OB4 antennae cable?

Thu, 30 May 2024 01:11:11 -0700

May i know if i can buy an OB4 antennae cable- the one that fits across the handle?