Carlsbro PA60 - Power Up Test

New resisistor and HT fuse in, powe cord into amp, plugged into circuit breaker (safety first).


Power on! Light! Wheeee!


Check HT fuse, just to be sure, and it's blown with no valves in the amp.


Dodgy capacitor is the most likely culprit according to Foxen and sure enough there's a bit of white fluff by the vent on one of the filter caps, which means it's probably dead, and this is further borne out by a quick voltage test across the caps. Best thing at this stage is to do a 'brute force' recap, so that's more money to spend.

Bah. But learning is good.

Plumbing the Depths

Retrovive RV-4 in C# standard -> Nine of Swords Burial at Sea -> Blackstar HT-DistX -> Peavey Firebass power amp -> Orange OBC 115

Sub. Ter. Ran. Ean

That is all.

Project: Carlsbro PA 60 Head

As mentioned previously Mr. Foxen of Ampstack has given me a Carlsbro PA 60 to work on.



From what I can tell from info-mining the internet this is a early-mid 70s model, probably a late Mk II. All other Mk IIs I've seen pictures of are point-to-point wired whereas this is on PCB, but I cannot find any reference to a Mk III so kind of assuming that at some point during the Mk II being in production it was changed to PCB construction.)

I have done initial solder refreshing and resistor testing. During the course of this testing I learned that sometimes resistors in circuit test at a lower ohmage than they are rated for and that by popping one end out of the board you can make sure they're sound. One of the resistors is duff (cheapo non-original, natch) plus the HT fuse has blown so that needs replacing. There was also a bodged in power cable which I've now removed.





Next I'm going to clean up the valve sockets, pots, input jack, etc. and after that is powering up with no valves to check voltages.

Finally here is a bit of random human interest stuff. The amp was apparently built by Trev and tested by people who as far as I know exist only as initials.

Things are afoot...

So, it appears to be all go here at Atomic Tangerine.

Not only am I soon to take on my second non-personal guitar upgrade, but I've taken on a project from Mr. Foxen.

The guitar upgrade is a simple electronics and pickups replacement for a dude who wants a bit more punch and versatility from his Epiphone SG. Pickups will come from IronGear.

The project from Mr. Foxen is a Carlsbro PA 60. Basically a 60 watt all valve amp head originally intended for PA use. Pretty much a win-win situation as I get to do more learning and Foxen gets more of his to-do pile finished.

Peavey Road Master - It's Alive!!

I have finally fixed my Peavey Road Master. Following the diagnosis a while back I have got the resistors that I needed, and replaced them (along with putting smaller LEDs in the front panel so they don't catch so easily.










And Eric the Destroyer is back in action! After all that it was a couple of duff resistors. Less than 50p's worth of parts. Feel kind of silly that it's taken this long to sort a simple problem, but I am quite new at this, plus I get the good feelings that go with having sorted the issue.

Doubleplusgood is that I can take Eric to band practice next weekend.

Boxing Day

I got a Black & Decker Workmate and a hot air gun for Christmas, meaning I can finally strip the finish off those guitar bodies I have lying around.

Also got a wee voltage tester, which'll come in handy, and I'll be off to Maplin in the next couple of days to get the components I need to (hopefully) finally fix the Peavey Road Master.

And finally here is a festive song for you:

Peavey Roadmaster - Welp...

So, that possible solution wasn't any sort of solution.

Which leads me to the bit I'd been putting off, getting out the multimeter and painstakingly testing all the resistors.

A long time and a lot of mumbling, headscratching, and messaging Mr. Foxen on Facebook I have identified two resistors that I get no reading from, and one that is about twice the value that shows on the schematic.

This puts the potential cost of fixing the problem into the dizzying heights of about £1.50.

I really hope this is the fix I need, otherwise it's time to get experts involved.