Hello, I bought this gem recently on ebay for a mere $75, and it is immaculate, surprised it didn't start a bidding frenzy! Well I got lucky there... Gorgeous little tablegram with 78 turntable. it was advertised as "Caps" replaced, and worked well as soon as I plugged it in, except for a loud "mains hum" which I straight away thought a little ominous, however dismissed it as maybe just normal for this model perhaps as with a little volume, it was drowned out. We (wife and I) enjoyed some Jelly Roll records for a bit then left the radio playing, when suddenly my wife exclaimed "what happened to the radio?" I popped up an ear to notice it had got very quiet and scratchy sounding, upon investigation I noticed another station was trying to muscle in on the one we were enjoying, but no matter how I tried to tune it I could get the station I wanted, but not the previous volume and clarity and even the record player suffered loss of volume and there was a "hot antiquey electronic" smell coming from it when I leaned closer and sniffed, not unpleasant just there, and noticeable a little more than I'd consider normal. I turned it off and the following day I noticed no improvement in sound quality and the mains hum too loud for my liking, so powered off and opened her up to find indeed all new caps with the exception of one large, particularly nasty looking electrolytic, which I snipped out immediately. It is rated 24+24 mfd with two wires coming out or the + side, but only one was connected! Hmmn thew plot thickens. I'm now wondering why it was left and why only one of the two wires was connected, and if the other was supposed to go somewhere? Before I simply replace it with a goody, if I can get a circuit, I'd like to peruse such to see if I can gander where that other wire may be meant to go as it seems illogical and a tad odd that such a capacitor would be put there if only half of it was to be used?
Anyhow if anybody has any views on this, please share! All comments very welcome.
Thank you.

It is rated 24+24 mfd with two wires coming out or the + side, but only one was connected! Hmmn the plot thickens. I'm now wondering why it was left and why only one of the two wires was connected, and if the other was supposed to go somewhere?

I have emailed you the schematic and notes.

Both capacitors are needed in that circuit.

A recap without replacing the filter and reservoir capacitors is hardly a recap! More than any other in a set, those electrolytics can cause major grief when they short out due to age. A burned out power transformer is a typical outcome.

I can only speculate as to why whoever worked on that set did not attend to that, but my guess is because they couldn't find a replacement off the shelf.

There are two ways of addressing multi-section caps like that one if a straight replacement isn't available: Gut the old one and "stuff" it with modern replacements, or disconnect it and install replacement caps underneath it. Whenever possible, I like to do the former but if there's room beneath the chassis many would simply do the latter as it's faster and cleaner (the old caps are usually filled with tar).

Thanks GTC, as I suspected! It would be illogical to have a 2 function cap if not needed! Thank you for your help! It was probably the output transformer overheating creating the hot smell with the faulty cap starving the circuit of power.
I think next time I'll have a thorough look regardless of whether somebody claims it has been re-capped!

Just a quick one, now I have more caps in my arsenal, would you recommend using 22μF to replace a 24μF, or putting 16μF and 8μF parallel to create 24μF? That would be more accurate, just wondering if 22μF would suffice or the more accurate option being better?

22μF should suffice as long as the working voltage is high enough. Such electros do hard work and need to be able to handle high ripple current.

Oh dear, new electro's soldered in, turned on and no mains hum whatsoever, but to my dismay the volume is less than a third of what it should be and sounds like a fuzz box, not a pleasure to listen to, so obviously it is damaged somehow, I'm hoping it's the 6m5 output valve as I have two newies on their way from Thailand, which I bought for my Astorm if it's not a valve I shudder to think what could have gone wrong with it, it sounded so loud and clear the other night and we were really happy with it... Now it's a radio fuzz box. I'm hoping it's not the power transformer, but if there's sound, it must still be ok one would hope?

Just guessing, but the rectifier tube would bear the brunt of carnage from a shorting filter cap most likely? Looking at the circuit it seems to be the component most in harms way after the transformer?

What's the DC voltage on the cathode (pin 7) of the 6X4?

The usual caution applies: warning, lethal voltage area.

Yes DC voltage measured carefully showing 267 volts, there are two big resistors in parallel, the other side of which is where the electrolytic cap (bad one) was connected to ground, I'm getting 170 volts there. Pin 7 is where the other 24μF positive of the cap was supposed to connect to, but nothing was there, it had been left disconnected, but has now been fixed. I have a 500V 22μF now going to pin 7 and a 450v 22μF going to the other side of the resistor where the bad cap was connected.

Rectifier and transformer seem okay then.

Valves are usually the last suspects, especially if it's been working.

Would check all solder work, especially that done by the "re-capper".

If you're hearing distortion on all stations at all volume and tone levels, then it's starting to sound like a problem with the output transformer or the speaker. If you have a spare 4 or 8 ohm speaker you can check that function.

Tracing the circuit, It seems the output transformer could be overloaded via the grid of the 6m5 if C18 was to short and I'm a bit worried as measuring the output transformer in the 20k range on my multimeter, I'm getting .59 which suggests an internal short or crook multimeter? Athough it gives a pop when I crack a 9v battery across it? Not sure there.

Can you post a link to the schematic? I cannot offer assistance without it.

I think my new acquisition is going to be consigned to the sick bay with my Astor until I can get a couple of output transformers, some cheeky stinker pipped me to the post on the ones I bid on via ebay in the last hour, so it seems I can only source them from Canada, unless I try modding line transformers, which seems a bit tricky, so maybe best just ordering two from Canada and awaiting their arrival.... I'll know next time, regardless of what claims are made, re-capping etc. just pull the bloody thing to bits and have a good sticky beak, before plugging in assuming all is well, I think it's like I find with cars as a mechanic, it's not what people tell you they've done, it's what they selectively don't tell you! Like they get too embarrassed to mention something they've cocked up... Leaving you up to your neck chasing a wild goose, when owning up would save a repairer a world of trouble. My fault really... I should never have taken anything for granted once I heard that hum. The lack of hum, now those electro's are replaced illustrates that. Silly me.

Let's not indict the O/P transformer just yet.

In the worth a try category: On the basis of 'the last thing changed is often the cause of the newest problem', you could try briefly disconnecting the new electrolytic and see if that improves things despite the expected hum. If so, then it would seem that's the reason muggins left that cap disconnected.

And yes, the car analogy is valid. Most of us would far prefer to confront an unmolested non-working set than one which somebody has "fixed".

No Robbbert sorry, GTC emailed it to me, but I don't have yours, if you email me a "test" email, I can send you the pdf. But I have come to the same conclusion as GTC that the output tranny is the likely culprit, apparently HMV's are prone to internal shorts and my multimeter is supporting that conclusion... Alas.