Hi-Fi Repair Hall of Shame

Welcome to the Hi-Fi Repair Hall of Shame, a page I’ve dedicated to bad repairs and repairers.

High standards of workmanship, attention to detail and best practice in electronics repair set Liquid Audio apart from most other repairers. Sadly, not everyone shares these values. This page examines really bad repairs, but prepare for pain, this stuff is bad.

Know Your Limitations

Electronics repair isn’t for everyone. As ‘Dirty’ Harry Callahan famously observed in Magnum Force:

“A man’s gotta know his limitations…”

There are some bad repairers out there doing awfully bad repairs. Of course, nobody is perfect, but none of what you see on this page should ever have happened. It’s impossible to do work this bad if you know what you’re doing.

Case 4 – Krell KRC Preamplifier

This one hurts the most, kinda like when you see the ex you really loved with a new partner weeks after you broke up. This is the most shocking bad repairs case I’ve ever seen.

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 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 guy on the east coast of Australia we’ll call William ‘Frampton’. No offence to the great Peter Frampton, but the guy’s last name rhymes with Frampton, change one letter and you’re there. Anyway, ‘Frampton’ supposedly improves this sort of equipment and this poor gentleman sent his cherished KRC over to Frampton. Here’s what happened.

Months later the customer got his preamp back. It didn’t work properly, the original Krell remote control no longer worked and the customer found a cheap Chinese remote control included in the package. When pressed, Mr Frampton informed the owner that he had ‘upgraded’ the KRC volume control and included an ‘improved’ $6 Chinese remote control to replace the clunky old machined and anodised aluminium Krell remote.

If even possible, things went downhill from here…

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. The KRC and KRC-HR use a logic-controlled stepped resistive attenuator for volume control. This the best and most expensive way to control volume.

The attenuator uses an array of 0.1% precision laser-trimmed resistors, controlled by an optical encoder, CPU and switches. The signal is routed through expensive nitrogen filled relays. Let me be clear – you cannot upgrade this preamp volume control – AT ALL. PERIOD. Krell did the engineering, it’s for us to try to learn something by studying it.

The customer became suspicious about the Chinese remote and non-functional inputs and this is when I got to see it first hand, a couple of years ago.

Wanna see some REALLY bad repairs…? Here we go…

A Normal Krell KRC

First off, this is what a regular Krell KRC preamp looks like. Check out this article where I completely restored one of these beauties.

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 Bad Repairs 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.

Oh shit. And yes, before you ask, this is the very same model. The entire precision attenuator board is missing. This is a critically important board. 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 mass of bodged in resistors and replacement caps that are too tall and very poorly soldered in.
This is not a joke, someone actually did this. Note the vaporized traces, appalling soldering, heinous flux residue and no attempt made to clean the board. This is a disgrace, pure and simple. 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 even go through the board. These are double-sided, multi-layer, through-hole plated boards. The cap is barely even soldered to the top of the board. Components need to have their leads inserted into holes on a board like this to guarantee correct operation.
Let’s just re-orient ourselves and take another look at this Silicon Chip remote volume control upgrade. I can only again say that no sane person would consider this an upgrade.
This replaces a CPU, switches and network of super-high 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 this was nonsense and that he “taught this stuff”. Yes, he said that.
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 when his ‘students’ graduate.
More evidence of something blowing up and nasty repairs. Remember – this preamp was perfect.

The Power Supply

Let’s take a look at bad repairs to the KRC power supply.

Not much to see from a distance other than a beautifully laid out symmetrical power supply.
Look more closely though and you’ll see stuff like this. What is this? Well, what it isn’t is a voltage regulator, which was right there, mounted to this heatsink. Why mounted to a heatsink? Because, by regulating, it dissipates thermal energy, which has to be removed.
Ah yes, here it is, bodged onto these traces, with some random diodes and a Lelon cap. No need to use the heatsink, of course, Krell were wasting their time with that. Needless to say, this component will die.
Nothing lines up and look again at that bodged voltage regulator. Appalling.
Once more, because I still can’t actually believe it!

We think Frampton 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 the board look like this underneath.

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 wiring
Another bodge
And finally this. What is this? Again note the woeful soldering and general mess.

Follow-Up

Unbelievably, there is a sadder ending to this story of bad repairs. After the unit was assessed by Jason, here in Perth, the owner contacted Frampton and expressed his disappointment. Frampton was unapologetic, explaining that he improved the volume control (yes, he actually said that). Helpfully, he explained that the attenuator board ‘broke’ and there were no more parts available from Krell (there were, we checked).

I guess he meant it broke like when you drive your car into a pole and it just breaks. Anyway, Frampton offered to again work on the preamp and against the strongest advice, the owner sent it back. He’s not seen it since and that was two years ago.

The moral of the story? Don’t EVER send any hi-fi equipment you care about to someone on the east coast Australia, with the name of Bill / William (rhymes with) Frampton.

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 particular repairer with a German name, many of you may know of him. He worked on a lot of gear, sometimes successfully, other times not. This sad case falls into the not category. I should point out that Vince is a lovely guy and I know he recommended this repairer in good faith. I’m sure this repairer did good work at one 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 much of the front panel controls, so many of these no longer work.

I found horrible flux residue everywhere due to poor quality solder and failure to clean up. Needless to say, the volume control never worked properly again. 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 joints
This 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 work
This 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 – ‘Modified’ 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..?! WTF?
Let’s just say about this that every bodgy automotive-style crimp was literally just sliding off its spade. No connector was the same as any other. It’s surprising this amp ever even turned on. What a disgraceful 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 complete write-off.
Nothing about this wiring is OK. Nothing.
As for this, we couldn’t figure out why someone did this or what the heck it was for. Check out the abandoned diode on the chassis bottom, in its own little puddle of solder. QC is non-existent.
Ummm, what IS this??
A recipe for poor sound quality, facepalm…
Why 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 who told her that, because he’s an engineer, he’s able to repair equipment like this.

I’ve got to be honest, this makes me angry. You can see from the images below that the repairer has ‘upgraded’ this circuit board to include a special new short-circuit, that prevented the amp from working properly. Low-quality contact cleaner and I use that term loosely, covered literally everything, and necessitated my thorough washing of the chassis.

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? 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 her 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…
This image is most alarming, t shows repair work this guy did to rectify the damage he caused. However, this potentially 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.
%d bloggers like this: