BassmanPaul

How are your speaker cables and what connectors are they using?

I may be wrong but I thought the 410HLF was a 4Ω box.

For interest what cabinet(s) and what impedance were you using with the amp when it failed?

Which is exactly what I do with mine.

Agreed! A single 15 is a very poor match for a 4x10.

Speakers don't have resistance they have impedance. Just correcting for accuracy.

My Mum and Dad flew over to visit. My Dad asked if we could take a day trip to see the Rockies. I was so sad to tell him that they were as far in the opposite direction as the UK is from Toronto. 😔 I would have loved to take him to see them.

I hope it works well for you. Enjoy!!

Make sure the cabinet you use matches the output impedance of the amplifier. IIRC that's 4Ω.

The Yorkville factory is a couple of miles East along Kingston Road from my home. they use Hammond transformers and always supply proper documentation and service manuals for their products. They are very reliable and don't sound bad at all.

<Sigh> Nice bit of quality diagnosis there! 🙄

Sad to say that I have a four channel 300W per sitting in my garage. If you were nearer I would have given it to you.

When I left the UK in late 1973 I brought with me both transformers from a SC150. I designed an amp around them and gigged it for a while before I sold it and went SS. I have to admit I loved Partridge transformers!

Then you have no choice but to stow it in the trunk! LOL

See if connecting the Effects Loop Send and Return with a signal cable helps any. An intermittent in the switches here might give what you describe.

Like most countries, Canada has it's problems. Here in the Greater Toronto Area we have our share of gun crime but not at a level as the US. We arrived here in late 1973 and Canada has been mostly kind to us. I ended up working for our electricity generating utility. Now retired I have a reasonable pension and an excellent health benefit plan that covers just about anything.

Me too! Especially after they banned me! LOL

Each vertical row of knobs constitute a channel with the sockets under them high impedance inputs for each channel.

If the amp has a dedicated headphone socket you pretty much just plug your headphones into that. Impedance is not that important when talking about headphones.

I believe that all Trace amps delivered their maximum power into 4Ω. Usually a combo will house a driver of an impedance to allow the amp to give it's max.

LOL I remember those old PA amps from back in the day. As for the TB50 it simply didn't have the power to produce a reasonable volume without distortion. Some folk like Lemmy just went with the crap and made it part of their sound. The engineer in me could not so I started on my quest to sound like a bass and not a distorted low tuned guitar! If you like what the TB50 does for you more power to you - enjoy.

The acme B2 2x10 is a three way design and I own four. I use two of them in a vertical 4x10 stack and they are wonderful. I can hear them easily and have no desire to migrate to another make/style of cabinet. The way they handle my Low B string has to be experienced!

I doubt it. Laptops and amplifiers are completely different animals and need vastly different diagnostic methology and tools.

@goingdownslow how's my old city doing lately? My four brothers are visiting us in a couple of weeks. Can't wait for their arrival1

You need to desolder the terminals of the jack using a 'solder sucker' then ease the socket off the PCB. Probably Hartke will be able to supply the correct replacement.