Customer reports that amplifier switches on but won’t click onto the source enabling it to play music. Found that half the power supply was not working, +63V rail was missing from which 5v logic and +24v rails are derived. Thermal imagery showed that the area of the PSU board with the regulator pass through transistors […]
NAD 319 Stereo integrated amplifier repair Read More »
Customer brought this vintage 80’s bit of kit to see if could get working as had sentimental value, they felt that the preamp was dead. Plugged in and there was no light on the preamp and indeed seemingly no output. However the preamp is powered from the power amp via a special cable, and could
Naim Audio NAC42 / NAC110 pre-amp/power amp repair Read More »
This came in because the owner said one of the input jack sockets has fallen inside the unit, and one channel not working as expected, so wanted that fixed and a general service. The plastic retaining screw was missing/broken and led to the connector being unsecured: Noticed a non-original pot fitted too, and a couple
Roland Jazz Chorus-120 repair and service Read More »
Customer states unit exhibited a burning smell and sparks coming from fan area back right side of unit halfway through a performance and asked me to take a look to see what the issue was. First needed to repeat customer concern before doing anything in case act of opening up case changes something. Powered up
Dynacord Powermate 600-3 sparking behind fan Read More »
Customer brought in a rather tatty looking Rotel RA-1000, clearly had a good life (think ‘ex-pub’), but had some issues, and wanted a longer mains lead fitting On testing, left channel no output, turned out to be a physically broken ALPS remote rotary switch, made of unobtainium, so had to effect a repair. Metal slider
Rotel RA-1000 service Read More »
Customer states that this active speaker (part of a pair) was cutting out during performance and felt it was overheating. Despite the fan coming on, I was able to repeat the issue on the 1000W dummy load with a particularly bass-heavy piece of music driving fairly hard – the bass amp would cut out and
Alto TS112A Trusonic overheating Read More »
Customer said their LK-1 “wasn’t behaving right” (pops/clicks between channels) so asked me to take a look. Several faults found (including some not noticed/mentioned by customer) on preamp board, including dead BC212L transistor shorted in the MC input (LH channel dead/buzzing), a faulty analogue switch IC DG309CJ causing popping switching to/from tuner input amongst other
Linn LK-1 preamp and LK-2 power amp full service Read More »
A friend reported intermittent issues with loud pops from one of speakers connected to his Cary 300SE monobloc setup. After some diagnosing swapping leads round to rule out the preamp, the issue stayed with one of the monoblocks. Suspected perhaps intermittent shorting of high voltage capacitor plates. Brought them over and found quite a number
Cary 300se Monoblock Amps Read More »
Customer states this unit was turned on after a period of non-use and apparently some electrical smell came out! Let’s have a look inside. There’s a pair of complementary MJ15003/MJ15004 output transistors, and oops some burned out resistors in the middle. One of them got so hot it had clearly melted the solder it was
Deltec / DPA 50S Amplifier – smoking hot! Read More »
A friend bought this amp but didn’t do anything when plugged in. Opened to find out the power board wire jumpers were cut from the preamp board inside. That would explain it. Apparently this is done so it can be powered externally from another device, and used just as a preamp, or split the preamp
Naim Nait 3 Amp no power Read More »
Apparently the power switch got kicked/knocked by accident and now doesn’t work 🙁 Can’t get to it easily so it’s front panel off time again, 51 million screws and knobs! (The switch is secured to the chassis behind the panel with two screws) Oops 1: Oops 2: A rather hard to find lever switch (centre
The Technics SU-3500 is back Read More »
Right hand channel output transistors BDV 65B and BDV64B shorted and took out 0.22 ohm emitter resistors which very quickly went open circuit. NOS ST brand BDV parts acquired and fitted to the dead channel, along with new 1W wirewound resistors Always wise to check output for DC offsets etc before connecting to speaker and
Bang and Olufsen Beomaster 5500 amplifier blown channel Read More »
This lovely example of 70’s Japanese workmanship came in with no output. Turns out +57V and -57V rail rectifiers (double-diodes D501 and D502) one had gone short circuit, and taken out both 2.2 ohm R501/R502 1/8W fusible resistors. As these were now unobtainium (CO8P-1 and CO8P-1R) they were temporarily replaced with 1/8W and couple of
Technics SU-3500 powers up but no output Read More »
