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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 20th Dec 2018, 8:50 pm   #21
crackle
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Default Re: Fidelity HF12

Oh I forgot to say, yes its working again, not the best record player I have heard, but I am sure this is the most basic I have come across.
It has a strange spindle arrangement for the platter. The platter wedges onto the spindle and the spindle turns in a bush fitted to the motor plate , a fibre washer acts as a thrust washer, fresh grease was applied to this, the motor bearings and the idler were given a drop of sewing machine oil.
Overall it was in fair condition under the record deck, there was some minor scorching of the ply around where the original 82 ohm resistor was.
The burnt resistor has left a lingering smell in my workshop, I must chuck it out.

MIke
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Old 21st Dec 2018, 12:59 am   #22
Techman
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Default Re: Fidelity HF12

That HT is a bit too low. Remember those Bush record players that tend to under perform a bit when the selenium rectifier starts to fail and drops the HT.

So especially for you, Mike, and seeing as I've got one here at the moment, I've taken a few voltage readings for you, but just note those resistors that I mentioned that were a little out of tolerance.

Mains voltage at the on/off switch at time of test = 244 volts.

Voltage after the dropper at the rectifier = 238 volts AC.

HT at first smoother = 279 volts.

Screen grid voltage at second smoother = 254 volts.

Cathode voltage of amplifier valve =21.1 volts.

I personally think that dropper resistor is too high and should be nearer the original 82 ohms, certainly not much higher than 100 ohms. Possibly the rectifier is slightly down as well.

There are various versions of that BSR deck. The one you have there is the version with a four position speed change and the neutral position as a separate switch, whereas the version of deck I have here has the five position speed change incorporating neutral as the first position on the knob. The turntable doesn't have a thrust washer, but has the bearing in the top of the hollow spindle, and it is VERY free running, although the circlip is lost (as usual).
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Old 21st Dec 2018, 7:21 am   #23
crackle
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Default Re: Fidelity HF12

Hi Techman and the others who have helped confirm my questions on here, thanks for your input.
There was zero information on this record player that I could find on the internet, yet they seem fairly common on ebay. Now there is a little more information, the voltage readings are very useful as a reference and I will put them on the circuit diagram for future reference.
But the owner does not wish to spend much on this repair, I certainly don't think he will want to spend an additional £10 on a new rectifier valve.
My view is, this cheap little record player is now having an easy time in its old age.

thanks
Mike

p.s. if you still have your one apart, can you please confirm what the resistance is of the OP TX primary, it would be useful to have that information as the TX in this one is not original.
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Old 21st Dec 2018, 7:53 am   #24
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Default Re: Fidelity HF12

Here is the final circuit diagram with Techmans voltage readings.
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Mike
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Old 21st Dec 2018, 4:18 pm   #25
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The original output transformer primary as fitted in the one here measures 238 ohms, so a bit of a difference. The speaker on the one you have there looks like it could possibly be a replacement too, although it's hard to say as there's also variations in the exact record deck fitted during production.

I understand what you're saying with regard to giving it an easier life with a lower HT voltage. I think we've all noticed that it still has the original BSR TC8 high output non-stereo compliant mono crystal cartridge fitted, so if this is still giving full output, then a lower HT can be got away with. I expect the OP and owner of the player is following its repair, so it's worth mentioning that the player will only really be usable for playing pre-1970 mono records with this cartridge, as it will damage later stereo vinyl pressings. So sixties 45 rpm singles such as Beatles, Shadows and Stones etc. will all be fine, also very good for playing 78s with the other stylus tip of the turnover cartridge. The fact that the original type of cartridge is still working tells us that the record player has been stored in the warm and dry for most of its life and not in a damp old shed. There's not a lot that can be done as regards a replacement high output stereo compatible cartridge as they're not available anymore, and modification for other types is expensive and not worth doing on a player like that. However, a medium output BSR X5M crystal cartridge will drive these amplifiers acceptably well enough for playing singles, but these go for somewhere around £37 these days, so again, not worth doing. I think you have to be realistic about these old, and simple record players - it's no good pretending, and as said, they are what they are.

If you've got a stylus pressure gauge handy, then it might be worth checking the tracking weight just to give the records that are going to be played on it a fighting chance - it is adjustable on these with a spring at the rear of the arm. They weren't all fitted with the TC8 from new, but I can't remember what the other cartridge type was.
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