'Mend it Mark' YouTube Channel

[David G4EBT]

I've just discovered the YouTube channel of 'Mend it Mark'.

Very well made videos and a presentational style which is a breath of fresh air.

Here are a few - there are a lot more:

This one is well above my pay grade. (Check out the powerful microscope!):

Diagnosis and repair of a Roberts RD60 DAB Radio: https://www.youtube.com/watch?v=RqKIKSzD6yw

Restoration of a 1970s stereogram in several parts:

part1: https://www.youtube.com/watch?v=pD6X9OAmIxs

Part 2: https://www.youtube.com/watch?v=iYl6w9Y-smo

Part 3: https://www.youtube.com/watch?v=rlqVTSfUZGs

Modifications to the stereogram and Fitting Bluetooth:

https://www.youtube.com/watch?v=FaeIQ59rQpE

Niagara Juke Box: https://www.youtube.com/watch?v=byWbdwI13S8

Caravan Switched Mode PSU Repair: https://www.youtube.com/watch?v=ndp6P8iVJY4

Hope you find them as interesting and informative as I did.

[jez_145]

Originally Posted by David G4EBT

Very well made videos and a presentational style which is a breath of fresh air.

Agreed. I like that he includes the odd mistake here and there such as accidentally cleaning the markings of fascias and grabbing hold of charged caps. Valuable reminders to us all!

Jerry

[Radio Wrangler]

Good wallfull of test gear, though I don't do tolo badly myself. That spectrum analyser at bottom right is either an 8568 or 8566 and if the latter once cost someone about a hundred grand. I've found a few stereo microscopes and they make life a lot easier especially with ageing peepers, but I still haven't found one with a camera port.

Nice attitude. Shows mistakes and how he gets back out of them. Good honest approach and nicely light on showmanship.

David

[G0HZU_JMR]

I'm pretty sure it's an 8566. I've got both the 8568 and 8566 here and the 8568 has the cal output BNC a few inches to the right of the main power switch. Mark's analyser doesn't show this plus I can see the little SMA 'IF' link cable that is only fitted to the 8566.

I hope it can keep cool in that enclosed space. It's probably fine and I guess it is one way to combat the fan noise it makes.

[radio69]

Looks familiar; I'm sure I've seen his boat on one of those 'Repair Shop/Fix It' type programmes, but I don't remember which...

He's got some serious test gear there...

[David G4EBT]

He's certainly very versatile - in this video he checks out and modifies a 1980 340 Watts per channel HH Electronics S500D Power Amplifier:

https://www.youtube.com/watch?v=InPosrQT548

Not too sure about his soldering on the tags of the small added transformer, just 'tacking them' on, rather than poking the wires through the tags. I've always taken the view that where possible, a joint should be mechanically secure before it's soldered.

He does have a way about him that suggests that any task is a pleasure - not a chore.

[ex seismic]

Wires poked through tags can of course be a right pain for us working on such things, trying to get them out. I must say I never bother. Way back I am sure I read an article somewhere about research done during the war and they decided there was no great benefit from putting the wire through the tag holes. Maybe someone here knows of such article or is it just a false memory of mine. Perhaps it was that there was no benefit to bending the wire around the tag, just poke it through the hole and solder.

Gordon G7KNS

[Station X]

It's OK to put wires through tag holes so long as you don't bend them back into a 'U' shape. Better to just bend to a dog leg which is easier to remove.

[chriswood1900]

David, thanks for the pointer, I enjoyed that first video and like his style, I will add it to my subscription list.

[hamid_1]

I watched the repair of the Roberts RD60 DAB radio with interest. A few years ago I was given one with exactly the same fault - dead, with the 5v supply rail missing.

I took a slightly different approach. I connected a bench power supply to the +5v rail. The display backlight came on, but there was no sound and no station name on the screen. At that point, without a circuit diagram, I didn't go any further. I admire Mark's persistance in fixing the no 5v fault by replacing the voltage regulator IC with a different one and redesigning the circuit, then fixing the no sound fault. It was quite an achievement to get the radio working again.

Seeing the time and effort involved makes it obvious why there are hardly any radio repair shops anymore. The cost of a repair would be regarded as not worth it by most people. But it's always good to see someone who has beaten the throwaway culture. I try to fix modern equipment myself too. Faults are often simple to repair, like burst electrolytic capacitors or shorted diodes in power supplies. And there's a great feeling of satisfaction when you get the item working again, even if the repair was quite easy.

[raditechman]

With the Roberts RD60 I wonder what caused both the audio output chip and the 5v supply chip to both fail.
I think if I got as far as fixing the 5v rail fault and then finding it worked but no sound I would give up. Or put it in the to do pile!

John

[DMcMahon]

Very interesting channel, am very envious of the microscope.

David

[David G4EBT]

'Mend it Mark' is Mark Maher, who runs his own little company 'Perton Electronics':

www.perton-electronics.co.uk/index.html

He repairs and restores just about anything from mixing desks to guitar amps, vintage radios, record players and turntables, test gear (scopes etc), vintage computers, juke boxes, and so on. He also does design and prototyping, and makes and sells a range of items, including mono and stereo Bluetooth modules he's designed for valve radios:

www.perton-electronics.co.uk/products.html

Who among us hasn't fallen victim to what can happen in an unguarded moment, as at 17.50 mins into this video, and uttered the words that followed 'ouch'!

'Repair (and shock!) from the Sargent EC225 Caravan Power System':

https://www.youtube.com/watch?v=ndp6P8iVJY4

It's rare to find a youtube channel with such well made videos by someone who knows what he's doing and gets on with it with no shaky camera work, waffling, fumbling or dithering. Nice too, that he has an enthusiastic disposition and so obviously enjoys his work.

[Sideband]

My God he's got some gear in that workshop!! Very impressed with the microscope for SMD work....!

[agardiner]

Thanks for bringing this channel to our attention David. Very entertaining and yes, we all want that wall of test gear!

[John123]

What a fantastic channel! The transformer repair on the Hantarex monitor chassis was above and beyond!

[DMcMahon]

Originally Posted by radio69

Looks familiar; I'm sure I've seen his boat on one of those 'Repair Shop/Fix It' type programmes, but I don't remember which...

He's got some serious test gear there...

Yes his face looks very familiar but I also do not know where from.

David

[Sideband]

I could watch that guy for hours! True professional. Reminds me to some extent of my last manager at Philips.

[Boulevardier]

Originally Posted by David G4EBT

I've always taken the view that where possible, a joint should be mechanically secure before it's soldered.

Me too, David. I was taught that solder was just for ensuring the electrical connection, and that the joint should already be mechanically solid before soldering. That maxim seems to have quietly disappeared when PCBs came along...

Mike

[agardiner]

Emailed Mark asking him to consider doing a workshop tour showing all his test equipment. He has replied saying a few people have asked for that and he will do one soon. Lovely!