Fidelity HF12 - worth doing anything?

[Peter Rabbit]

Last post should have said "switching the unit ON establishes the neutral to chassis " etc.

['LIVEWIRE?']

Yes, Indeed, P.R. If the switch is working corrctly there should be continuity between the Live mains lead and the rest of the circuit, and between the Neutral lead and chassis as you've described, with the switch 'on', and no connection between either mains lead and anything else with the switch 'Off'

[crackle]

Can you please confirm, was the terminal on the back of the switch, where the grey and red resistor and the green wire connects to, snapped off short (damaged). If it was then you will have to replace the whole control, you cannot rely on a solder joint to the snapped off stud.

Mike

[Peter Rabbit]

Looks like it was the soldering between the two tthat has broken rather than a terminal snapped off. I'm going to try re-soldering at weekend and if it seems like it won't hold then I'll look for a replacement unit.
Any suggestions as to make & source if something that would fit the bill if it becomes necessary ?

[crackle]

If the whole of the terminal is still there then there is no reason why you cant resolder to it.
First clean off all the old solder with a hot soldering iron. There should be a hole which you can push the wire of the grey and red resistor through. Then apply the hot iron and fresh fluxed solder to the join until the solder flows around the joint. Make sure the green wire has a clean tinned tip about 4mm long and hold the green wire on the joint. Apply some solder to the tip of the iron and place the tip of the iron with the small blob of solder over the tinned tip of the green wire till the solder flows nicely around the joint.

To save going back and forth to the previous thread I will post the circuit again here.


Mike

[Peter Rabbit]

Mike,
Thanks very much for this. Hope to give it a go at weekend but a bit warm for indoor work so garden taking priority.!

[Peter Rabbit]

Further inspection of break between resistor and switch shows no stud so not able to clean back and reconnect. Tried re-soldering and got a firm connection but when powered on sparks at switch and blows fuse in plug. Short of some sort but don't know exactly where. Photo of joint attached - not elegant but if you can see any obvious reason for shorting I'll have another go but not likely to invest much more into this! Continuity at switch still ok tho.

[Station X]

Can we have a picture looking straight on to the back of the switch please.

['LIVEWIRE?']

1Meg Log pots. with D.P. Switches are available from several suppliers at reasonable prices. It would be a relatively simple job to replace that volume control with a new one. Just make a careful note of what is connected to each terminal before removing the existing control. Many modern pots. have fully insulated nylon or plastic shafts , which, IMHO, is an added safety factor.

[Station X]

For testing purposes the faulty pole of the switch could be bypassed.

It looks like the green wire may be shorting to the casing of the switch, but it's difficult to tell from the picture.

[crackle]

It looks like the solder blob may be shorting onto the body of the switch.
see red arrow.
If the solder tag has broken off then you will never be able to get a reliable joint.

As mentioned you could bypass the switch for now and solder the resistor and green wire onto the tag with the green arrow purely to test if the amp is working, BUT BEWARE THIS LEAVES THE PLAYER IN A DANGEROUS STATE.

The record player is not safe left in that condition so keep your hands well clear whilst it is connected into the mains. Even when this switch is turned off, it may seem that the player is off but there will be mains voltages potentially on the chassis due to the isolation of the neutral when the switch is turned off.

Please be careful, the white wire that the green arrow is pointing to seems to be marked with blue or black. This is wrong as it should be the mains live wire, and if it was going to be marked it would have been better in brown, or red as a last resort. It is the other white wire which should be the mains neutral (blue) and that one will connect to the chassis when the switch is on.

Mike

[Peter Rabbit]

More good advice here - thanks. Back of switch is hard to photograph but I've had a go.
Solder blob is in contact with body- can I file blob down to create a gap and/or insert insulation of some sort between ? Not keen on on bypassing the switch if possible- already at edge of my comfort zone! BTW, buzz test difficult as connections to cartridge have been wrapped in insulating tape and can't get screwdriver across without removing, which may just reveal another issue.
Whatever, not doing anything else till get a couple more 3amp fuses.!

[Peter Rabbit]

PS.
Red arrow very clear but can't see a green arrow. Any colouring on mains cable already present, not mine! However it's the other side that goes to the chassis.

[GeoffK]

This pot wiring is in quite a mess, the fuse is blowing because there is a short circuit between live and neutral wires, possible caused by solder debris on the switch plate between contacts or wire either connected wrong or wire strands shorting together. The live connections should be totally isolated from the metal switch case and chassis.
The sketch shows the connections. And instead of blowing more fuses, once it is wired up (AND UNPLUGGED FROM THE MAINS) continuity tests should be carried out from the live plug connection via the fuse to live switch side and neutral to neutral side and make sure there is no direct connection between live and neutral. A multimeter on the low resistance range is better for this test, rather than a continuity buzzer or battery and bulb. The chassis MUST go to the blue neutral side of the mains.

['LIVEWIRE?']

I can only second Geoff's comments in post #54, and repeat that I would replace the volume control & switch assembly if one of the tags of the original was broken off. I appreciate that this would be easy for me as I have been working with electronics for almost 50 years, it's not a difficult job to do if care is taken with wiring the connections correctly.

[Peter Rabbit]

Thanks Geoff & Livewire. I'm using a multimeter for testing continuity but haven't used the routes suggested so I'll do that next after cleaning up any solder debris around the resistor connection, which will have come from my somewhat heavy-handed re-soldering efforts. Job for tomorrow.

[crackle]

Sorry I uploaded the wrong photo


This is an enlargement of your latest photo,


The politest description I can give of the soldering is DANGEROUS, and I am not surprised sparks flew and fuses went pop.
I think it would be a good idea if you asked for any forum member who may live near you to help sort this out.
There is a section where you can request repair services. https://www.vintage-radio.net/forum/...play.php?f=145

Or someone may take pity and offer some free practical help.

Mike

[Peter Rabbit]

I have learned there is a vintage record player/radio museum of sorts in local town so I'll have a look there first as it's near. If no luck I'll go via the service/repair link you have supplied. To all intents and purposes though I think this particular thread can be brought to a close.
I assume it remains on the forum for reference for a while ?
Thanks again for help and guidance

[Techman]

Sorry to have to state the obvious "again", but back in post 35 I already suggested that you bypass the on off switch if it turns out to be 'dud', and make your connections directly to the mains input tags on the switch where the two core white wire connects. The player WON'T be any more dangerous, as you'll be removing the mains plug from the wall socket EVERY TIME you do any work on the internals.

You're making VERY hard work of what should be a very simple job, but you really MUST improve your soldering skills!

You've now got your meter and you seem to know how to use it, so that's all good. A couple of points to remember - only use the resistance/ohms/ continuity ranges when the player is completely disconnected from the mains. NEVER use any of the 'current' ranges, ie, Amps, mA, uA etc. You will need instruction on how and where to use the meter on these rages, as getting it wrong WILL result in a BANG and destruction of your meter and possibly the record player! Always use the meter on the 600 volt ranges when checking AC or DC voltages on your player. Only use the lower ranges if you KNOW the voltage is going to be low, such as perhaps when checking the 9 volt battery in your smoke alarm etc.

There's been a lot of people 'viewing' this thread. I noticed that the viewing number was up to nearly a thousand within the first couple of days of you starting this thread, so there's a lot of interest in seeing an old cheap and cheerful record player being revived - either that or they are waiting to see you blow yourself up!

I hope you've got one of those Chinese cartridges on order, as it'll take a while to come from China? You need a new cartridge if you're going to play modern records and even if you're not, it's pretty certain that the old cartridge is likely to be duff. It doesn't really matter whether the cartridge will be needed or not, or even if it turns out not to be very loud when driving the single stage amplifier - they're £1.29 with free postage to the UK for goodness sake, so just get one regardless!

[Peter Rabbit]

Phew Techman, quite a lot here.
1) It wasn't clear which connection you were talking about in post 35 and still isn't. Do you mean all other connections to the "pot "?
2) I'm making hard work of this because after never having done anything like this in 70 years it IS hard as far as I'm concerned.
3) Agree my soldering skills need improving but only soldering of mine on this is the reconnection of the resistor/green wire to tge pot.
3) Taking my time with multimeter so only been using diode/continuity position in ohms setting and dc setting for checking batteries (though not smoke alarm which is wired to mains).
4) no, haven't ordered a Chinese cartridge- got an issue with anything from there that costs so little, including postage, suggests very cheap labour.
5)I've an old Tellux player that I can probably transfer cartridge from for test purposes even tho won't fit arm as permanent replacement.
6) Tidied up the lump of solder so no contact with casing and motor running quite well again.