AMPTEk

20/05/2026

Had a fender 1000 performer in for repair, the amp kept wanting to change channel, usual fault with these amps and seems most fenders is putting power resistors and the 16v zener diodes hard on the board hence with the heat the board burns and dry solder joints, I replaced both diodes but used stand off to help air flow. Job done

12/05/2026

Had another couple of repairs in from the same customer, a fender Pro that was sounding a little rough, turned out to be both output valves had leaky control grid according to my orange tester. The one thing with these amps the mains transformer can't be set at 240v, so my little brain is thinking is because the heaters have a higher voltage on em? Anyway, new output valves check bias job done. Next was a Lazy J amp that's hand wired, similar to a 5e3 the customer said it had a strange intermitant hum noise, if he pushed on the back panel or the left valve the hum would start, I removed the back panel switched the amp on and pushed the offending valve, I could see as I moved it the wire on pin 5 was moving in the solder joint, resoldered that joint and there was a few more in the amp I wasn't happy with, gave both a good testing, another happy customer.

26/04/2026

Had a wem dominator mk111 in for repair and to mod channel 1 as a fender delux. Had to redue some solder joints that were a little duff, replaced all filter caps as one was bulging, and another had its inerds escaping. Tested all valves one of the EL84s was worn, so replaced em but the bias was going way up. It took me around 3 hours to find it the old mullard valves pins 1 and 2 are linked internally but new valves aren't so looking under the chassis the factory had connected to pin 1 hence I had no bias, put it this way my language cannot be repeated hear lol.any way finally sorted it and does the first channel have some, I also used the bright switch to connect a capacitor across the cathode resistor, all to what the customer wanted.

05/01/2026

I've had a few marshall amps in for repair, avt50 output chip blown, I replaced it but found it had caused a lot more damage wasn't worth repairing, all the others were just noisy pots and bad solder joints. Had a fender blues junior original come in, the customer said it has low volume and a strange noise, turned out to be output valves tested worn, and first preamp valve 12ax7 was microphonic replaced all 3 revised amp another job done. I've got 2 amps in marshall mg100dfx blown output chip and noisy fan, the other is a Hartkle H2500 low volume, job for today.

21/05/2025

It's been a long time since I've posted on hear. Been busy with repairs and also trying to sort out the house and garden,so much to do.
One thing I keep telling customers about is the fact we are not 230v in this country, the amount of amps especially fender I've had ro adjust the voltage setting, not just me but other techs aswell. I've had 2 repairs last week one was a yamaha mixer 230v input mains transformer got hot so it's got shorted primary turns, the other was a mackie srm450 pa speaker, mains transformer shorted primary winding, but it's made in China poor quality enameled wire used, over £250 to be rewound, so the customer decided to scrap it and by replacement. It has gone a little quite repair wise at the moment hope it picks up soon.
All the best everyone if you've read this thanks.

13/10/2024

Good morning, sorry it's been a while had a lot to sort out, anyway I've had in for repair a selmer selectone the customer said he wasn't sure if it was worth bothering with. Who ever he bought it off decided to cut the bottom of the cabinet off and turn it into a head. Got the 2 chassis out and started to look at the power amp first, luckily the transformers are OK but quite a few components had to be changed, tested the valves they were worn, the gz34 rectifier valve was missing. Changed the filter capacitors and all components that needed replacing with only the rectifier in I brought the voltage up slowly on my variac. Replaced all other valves powered it up, the amp worked great now fo the pre amp that took a little longer, but cutting a long story short it's sounds great to me, it's got a lovely tremolo on it too. The customers happy picks it up next week.

23/07/2024

Had in for repair a Dynacord speaker with a rattle when in use and if you moved it, after an hour getting into it I found the cause..the actual magnet screws on the back of the horn had worked loose, tightened em up put back together sorted.

26/06/2024

Had a lovlely old fender princeton chorus in for repair..complaint was sounding very top endy reverb not very strong, and foot pedal not working. I got the chassis out and the first thing I spotted was the treble control had been changed but without the metal bracket, a closer look showed that the bracket connected the rest of the tone stack so I put links of wire where the bracket would be. All working OK next the footswitch, one of the leds had dry solder joints and both switches not working..took both apart gave em a clean re assembled soldered back in place, pedal now working. Another job done

18/04/2024

28/03/2024

Hi everyone, it's been sometime since I've said anything on here.. moving house was and a bereavement in the family.
I've had 3 valve amps in from Robannas, a fender super sonic just needed the pots cleaning and the mains voltage tapping adjusted for 240v. A blackstar HT stage 60, EL34EH output valves needed replacing they were very noisy and the phase inverter valve ECC82 worn. The complaint was its quiet. Someone had plugged the speaker into the emulated output jack..sorted. Next a lovely Fender hotrod deville but looking very sad for itself.. the power light came on but nothing..took the chassis out and noticed one valve missing ECC83 hence no output.. 6L6GC output valves tested ok but very noisy. All filter caps needed replacing some had there inerds spewing out. Again I changed the voltage tapping for 240v and set bias, another job done amps returned to Robannas.

Next job in a marshall valvstate VS100R. A service and checking over, the first thing I spotted was the speaker tag had come away from the speaker frame and rubbing on the cone, the head of the rivet had broken off new one fitted..the ECC83 valve tested worn and was noisy. Cleaned the pots and jack sockets and vacuumed the amp out..loads of spider bodies lol. Job done.

Next, Matrix MA10X amp had a loud hum when switched on, turned out to be bad solder joints on input jack, it took longer to get the chassis out than do the repair but sorted.

Next job a yamaha powered speaker MSR400..tweeter not working, got the amp out of the cab, looking over pcb first I spotted a 100uf electrolitic capacitor with its top bulging.. got the board out to replace and noticed a long crack in the pcb obviously been dropped..repaired the crack print with wire, rested it all working great job done.

If you've read this thank you..
bye for now.

Cheers Bob.