Welcome to one of my most popular pages, the hi-fi repair Hall of Shame, dedicated to bad repairs.
Industry best-practice drives Liquid Audio’s obsessive care for hi-fi equipment. Not all repairers share this approach though and the results often come to me for repair, clutched by disappointed owners who’ve learned this the hard way. This page examines the inevitable results of people who shouldn’t be working on electronics doing it anyway: really bad repairs.
Know Your Limitations
Everybody’s good at something and I’m a firm believer in doing what you are good at, to the best of your ability. I’m not good at tax stuff, but my accountant is. Similarly, electronics repair isn’t for everyone, any more than macramé is. As Dirty Harry Callahan observed in Magnum Force:
“A man’s gotta know his limitations…”
Some technicians simply shouldn’t be working with electronics. This isn’t a judgement, just a statement of fact. Those who wreaked the havoc you’ll see below might mean well, but that isn’t enough. We wouldn’t have these bad repairs if people acknowledged their limitations and pursued things they are good at.
Check out this modification abomination, rendering this wonderful old Marantz CD player unserviceable. The obvious question is why? It’s hard to know, but I’d suggest the perpetrator read about improving the clock on a forum and failed to understand that the implementation is more important than the components. Equipment can be improved, but not like this.
This is how the insides of a CD85 should look. Things are neat, tidy and serviceable.
This is the insides of a ‘modified’ Marantz CD85. Note the homebrewed, hardwired PCB at the bottom left, transparent additional panel and birds nest wiring.Here’s a closer look at this board. Note the extreme home-made appearance, but wait until you see how it’s attached…A closer look at the board. I know what you are asking – “Mike, what does this do..?” In truth, I don’t know. It could be some sort of additional power supply, or maybe a new crystal oscillator.Here’s a clue – an ovenised crystal oscillator on the underside. This board is probably a home-made clock module.Check out the build quality though and how it is attached to the transparent cover. Is that chewing gum holding a wall plug as we call them in Australia? Is that more chewing gum under those capacitors…?Yep, chewing gum, or Blu Tac, could this be any worse? This work was apparently done by “an expert in CD player modification”.Some sort of hot glue or epoxy perhaps, covering these 1-watt resistors.And for safety, the voltage selector has been left hanging inside the chassis, where the pointer no longer refers to any particular position. What voltage is this set for..?
Case 4 – Krell KRC Preamplifier
This one hurts the most, like when you see your ex with someone new just weeks after you broke up. My good friend Jason @ The Turntable Doctor shared this tragic case with me and we’ve talked about the need to get the story out ever since. This is certainly the most shocking bad repairs case I’ve ever seen.
This is the complete package – a Krell KRC-HR in this case, including separate power supply and remote control. From the outside, both KRC and KRC-HR look the same.
There’s a ‘repairer’ on the east coast of Australia we’ll call William ‘Frampton’. No offence to the great Peter Frampton, but change one letter and you have this guy’s last name. Anyway, ‘Frampton’ supposedly improves hi-fi equipment, so a Perth local sent his cherished KRC-HR over to him. Here’s what happened.
First Signs of Trouble
When the customer eventually got his preamp back, neither the preamp nor the Krell remote control worked properly. He found a cheap Chinese remote control included in the package and when pressed, Frampton informed the owner that he had ‘upgraded’ the volume control and included an ‘improved’ $6 Chinese remote control to replace the clunky old machined and anodised aluminium Krell remote… Classy.
Oh boy, someone try to stop me writing the rest of this…
The Krell KRC is a superb preamp. If you want to see more, check out my KRC-HR restoration. Costing over $10,000 AUD in the mid-1990s, there aren’t many improvements you can make to a preamp like this and any real repairer would know enough not to try anything silly.
The KRC and KRC-HR use logic-controlled stepped resistive attenuators for volume control. This the best way to control volume. The attenuator uses an array of 0.1% precision laser-trimmed resistors, an optical encoder, CPU and switches. The signal is routed through expensive nitrogen-filled relays.
Let me be clear – you cannot upgrade this volume control – AT ALL. Krell did the engineering, it’s for us to try to learn something from it. It’s outrageous and foolish to think that you could improve the volume control implementation in this preamp.
Note the uppermost board, with the rows of chips, precision resistors and relays. Note also the volume encoder, top left. Spinning the encoder generates a series of pulses. These pulses are read by the CPU, which instructs the IC switches to select the correct resistor string to produce the commanded volume level. This is precise volume control, it cannot technically be improved. Typical of Krell, there is very little wiring and there is NO FLUX RESIDUE!Standard, unmodified Krell KRC. Dusty, yes, but see how all the capacitors fit correctly and how neatly they are installed.
The Frampton Krell KRC…
Let’s take a look at the ‘improved’ KRC, after some bad repairs by Mr Frampton. We’ll start with the preamp and then look at the power supply.
Yes, this is the very same model. The entire precision attenuator board is missing. In its place is a Silicon Chip remote control volume kit – that’s the smaller green board and cheap ALPS volume pot. Note also the maze of ribbon cable, the bodged in resistors and replacement caps that are too tall and poorly soldered in.This is not a joke, someone actually did this. Note the vaporized traces, appalling soldering, heinous flux residue and dumpster-dirty circuit board. This is an absolute disgrace, seriously, this is the worst work I have ever seen.
Frampton probably destroyed the precision Krell volume control board by accident. Nobody of sound mind would assume they could ‘upgrade’ it, let alone try to.
With the top board vaporized, this guy had to bodge all the top row of board mounted connectors to the bottom board.This is, without doubt, the worst work I’ve ever seen. WHY???Why use an axial capacitor, or a neatly mounted a radial one, when you can do this? Note the leftmost component lead doesn’t go through the board as it is meant to and is barely soldered to the top of the board. These are multi-layer, through-hole plated boards. Components need to have their leads inserted into holes on a board like this to guarantee correct operation.Let’s take another look at this Silicon Chip remote volume control upgrade. Again, no sane person would consider this an upgrade.This replaces a CPU, switches and network of super-precision 0.1% metal film resistors. Why use precision parts when you can improve things with the Studio Series Control Module with Chinese low-precision capacitors and resistors..?Transistor and ribbon cable bodgery. Note the bodged blue relay. This replaces one previously on the top board.Almost everything here is ruined. This preamp was someone’s pride and joy. What you see here is the total destruction of a beautiful and irreplaceable piece of equipment. When asked how he could possibly have produced work of this standard, Mr Frampton cheerfully replied that he “taught this stuff”. Yes, he said that. I’d ask for a different teacher kids…These caps are too tall, the values are wrong and they are soldered in so badly, it looks like a child did it. This guy teaches soldering..? Heaven help us.More evidence of something blowing up and nasty repairs.
The Power Supply
Let’s take a look at bad repairs in the KRC power supply.
Not much to see from a distance other than a beautifully laid out symmetrical power supply.Look more closely – what is this? Well, what it isn’t is a voltage regulator, which should be there, mounted to this heatsink. Why mounted to a heatsink? Because it dissipates thermal energy, which has to be removed.Ah, here it is, with some random diodes and a Lelon cap. No need to use the heatsink, of course, Krell wasted their time with that. This component will die and I’ve never seen work this bad – ever.Nothing lines up and look again at that voltage regulator. Easily the worst workmanship I’ve ever seen.Once more, because I can’t believe it…
Frampton likely blew up the power supply by shorting something in the preamp. Here’s some more evidence.
There isn’t meant to be an insulating sheet under this board-mounted transformer.Nor should there be residue like this.
The mains wiring isn’t meant to be tacked onto this point here under the transformer. He’s done this because he vaporized more traces in this power supply.Bodgy tacked-in wiringAnother bodgeAnd finally this. What is this? Again note the woeful soldering and what appears to be a shorted pair of legs on this device.
Follow-Up
After the unit was assessed here in Perth, the owner contacted Frampton. Frampton was unapologetic, explaining that he improved the volume control (yes, he actually said that). Helpfully, he explained that the attenuator board ‘broke’ and that parts were not available from Krell (they were).
I guess by ‘it broke’ he meant like when you spill petrol on your lawnmower, drop your lit cigarette butt and it ignites, ‘breaking’ the lawnmower or drive your car into a wall because you are looking at your phone and break the car…
Anyway, Frampton offered to ‘fix’ the preamp (it cannot be fixed). Against the strongest advice, the owner sent it back. He’s not seen it since. The moral of the story, don’t EVER take hi-fi equipment to this repairer.
Case 3 – Harman/Kardon PM-655 Integrated Amplifier
This case of bad repairs came to me in February 2018. My customer bought this new from Vince Ross Audio, back in the day. It worked well for years until it developed a fault.
Nice amp the PM-655. From the outside, all looks normal.
Vince used a repairer with a German name, you may know of him. He worked on a lot of gear, sometimes successfully, other times not. This case falls into the not category. I should point out that Vince is a lovely guy and used this repairer in good faith. This repairer likely did good work at some point, I don’t know how it came to this.
Anyway, this repairer destroyed several boards in his attempt to repair a volume control. The guy used the lowest quality Jaycar volume pot and ribbon cable. He destroyed traces associated with the front panel controls, so many of these no longer work.
I found horrible flux residue everywhere due to low-quality solder and failure to clean up. Needless to say, the volume control never worked properly after this. Well, it does now, I had a look and did my best to rectify this appalling mess and make the amp reliable for my customer.
I serviced the unit and fixed the volume problem. Needless to say, the owner was horrified when I showed him these images and explained what happened. He couldn’t believe it. He confirmed for me that it had only ever been to the German repairer.
Bad Repairs…
A closer look after removing the lid reveals this mess. Flux residue everywhere and this is just the beginning.This is the bodged volume control repair. Note the cut quality factory wiring loom, and the shitty, bodged in ribbon cable, just tacked onto the underside of the board. One question – WHY??This is an abomination. My soldering at 16 years of age was ten times better. Who would leave a job like this??Look closely at the jointsThis is appalling, note the unsoldered joints and mass of flux residue. This job should never have gone back to a customer like this.Note the cut trace ‘bodges’ here and general mess. This I think was in an effort to fix the mess he’d made of the front panel controls.More shoddy workThis is how the boards should look. You’ll note I’ve cleaned away as much of the mess and re-worked many of the joints.
Case 2 – Perreaux PMF 3150 Power Amplifier
This incredible bad repairs case came to me via my good friend Jason, otherwise known as the Speaker Doctor and the Turntable Doctor. Jason does fantastic work and we often share stories and compare cases like this.
Anyway, this amplifier came to Jason recently, for repair. The owner bought it for $900, from a guy who ‘upgraded’ it. You be the judge on whether these are upgrades and whether $900 for a destroyed amplifier is good value for money…
Bad Repairs…
Interesting… What does this do?Panasonic FC caps in the foreground, but what the hell is that behind them?? It looks like an attempt at a soft-start circuit, you can be sure it didn’t leave the factory looking like this.We couldn’t fathom the logic of installing a 40 Amp poly switch in series with the outputs. It will sound really bad and it trips at 40 Amps. What sort of speakers did this guy think needed protection, only once the output current reached 40 Amps? 40 Amps!!! So 30 Amps to the speakers was OK, just not 40 Amps..?!It’s surprising this amp ever even turned on. What a mess.For reference, this is what SHOULD be there in the image above. This is a power distribution board, with factory Perreaux caps, small diodes, bleeder resistors and wiring. I guess the idiot who removed this knew better than Perreaux’s own highly regarded engineer Peter Perreaux! If only Peter had asked this guy how to improve the 3150… NOTE – the factory Hitachi MOSFETs in this standard image on a non-destroyed 3150.Now look again at this mess. Note the missing factory power distribution board, the bird’s nest of crappy wiring and the non-factory MOSFETs. This last point is critical. The amp has low-quality, non-standard and unmatched replacement output devices. It cannot operate correctly like this. The only solution is to purchase around $500 of rare replacement MOSFETs. Sadly, when you add that cost to the missing factory power board, this once great amplifier is now a write-off.Nothing about this wiring is OK.As for this, we couldn’t figure out what the heck it was for. Check out the abandoned diode on the chassis bottom, in its own little puddle of solder. QC was non-existent on this job.Ummm, what IS this??A recipe for poor sound qualityWhy anyone would do this is beyond me. If you don’t know what you are doing, leave it alone! Anyway, what is this wiring??
Case 1 – Kenwood KA-5700 Integrated Amplifier
This lovely little amplifier came to me via a very nice customer. She’d taken this otherwise good amp to a local repairer. You can see from the images below that the repairer has ‘upgraded’ this circuit board to include a special short-circuit that prevented the amp from working properly.
To add insult to injury, when my customer took the amplifier back to Mr Radio Waves, he had the audacity to tell her that the unit was now too old and damaged to be worth repairing! Seriously? But he did the damage?!
Thankfully, this lovely customer brought the unit into me and I’ve repaired it. The KA-5700 is now working perfectly, though a little worse for wear after its near-death experience at the hands of Mr Radio Waves.
Bad Repairs…
Everywhere this guy removed capacitors, he damaged the board. He didn’t even clean away the flux, nor did he properly repair the parts of the board he damaged.Here, you can see the same area after I re-worked it. Given the damage, its a solid, reliable repair.What on earth is going on here..?Lifted traces…General bodgery caused by poor soldering and desoldering tools and technique, leading to bad repairs.This image is most alarming. It shows repair work this guy did to rectify the damage he caused but this caused a short, where this wire jumper sits right next to these two other pads. Note that the pad that the guy destroyed is now floating on the board.
