Restore an HMV 2127

[SurreyNick]

To be entirely honest Mike I haven't understood your contributions other than at a superficial level, which is of course entirely due to my ignorance. Please don't be offended by my lack of acknowledgment to your posts. My hope is that as my knowledge grows as I resurrect this record player I come to properly appreciate the points you are making.
Nick.

[SurreyNick]

Service Manual for Plessey Type D autochanger / HMV48700 deck

You can get a copy of the Service Manual for this deck from http://www.shopingathome.com/Circuit...0Lists/HMV.htm

It is a comprehensive 41 page manual, with plenty of exploded views and covers; Operation, Maintenance, Adjustments, Faults and Spare Parts, and is available as a PDF download or in printed form/CD.

Nick.

[Edward Huggins]

That's very useful. Even so, we rarely come across them as they were mainly used on early 1950s period HMV Radiograms, Table Radiograms and I think one portable Record Player.

[SurreyNick]

Other than the usual preliminary checks prior to powering up, do you think I should replace any of the caps in this machine? The smoothing can looks to be in good nick and I'll take it out of circuit to do a quick electrical test, but in the absence of service data, which I simply can't find for this player, I don't know if I should automatically replace any of the other caps.

It's very difficult to get a clear view of all the components and if I don't have to dismantle the machine to get at them it will be a bonus.

Views?

Thanks

Nick

[ms660]

The audio output g1 coupling capacitor at least, can you post an underneath view of the amplifier chassis?

Lawrence.

[SurreyNick]

Pics attached. Best I can do without dismantling the machine. I have taken plenty more if needed
N.

[ms660]

That brown hunts capacitor that's connected between pins 1 & 9 of the ECL83 is the grid coupling capacitor to the audio output (pentode) section of that valve, that must be changed at least.

Check the HT electrolytic can for any signs of bulging of the can or the base also check the base and the tag rivets for any signs of chemical leakage, if all's ok it might survive.

You should be able to reverse engineer a schematic for that, it would be good practice for you and also good for the forums collection of odd ball schematics (stuff not on Pauls downloads or DVD)

The red and silver resistor and the electrolytic capacitor connected across it are the triode sections cathode bias resistor and bypass capacitor, the resistor is a 2.2k job, the 100 k resistor connected between the triode section anode (pin 1) and the pentodes screen grid (g2..pin 8) should be the triodes anode load, what looks like a 330k? resistor appears to be the pentodes g1 (pin 9) return resistor, the 470k (nearly shorting out to chassis) appears to be a feedback resistor from the pentodes anode (pin 6) via the anode tag of the sound output transformer to the triodes anode (pin1), both the screen grid and the HT feed to the sound output transformer seem to be connected to the HT filter capacitor, the big dog bone resistor is the HT filter resistor.

Any errors then guilty as charged.

Hope this will help you as to what's what circuit wise.

Lawrence.

[SurreyNick]

Thanks Lawrence, I'll replace as recommended.
Happy to have a go at generating a schematic. If it were a 30s TRF I'd be very confident but I'm not quite as confident with this, although thankfully it looks quite straight forward. Let me have a go and perhaps someone would be good enough to look over it before I post it up
Nick

[Edward Huggins]

Originally Posted by SurreyNick

Just been reading the 'reviving your old record player' guide on this forum and it mentions that portable domestic record players with the facility for an add-on speaker/amp unit for stereo reproduction are quite common.

This got me to wondering if this is this a mod that could be made to a record player such as mine?

For the moment I don't have any plans to do anything other than get this player working properly but I would still be interested to know.

Nick

Don't think me harsh, but I would abandon any plans to install a stereo cartridge, re-wire the arm and source/build a stereo converter. As previously advised, the Tone Arm in the Plessey unit is totally unsuitable for satisfactory stereo performance. Just concentrate on getting what you have working as an original, self-contained Mono unit.

[SurreyNick]

No offence taken Edward. I have no plans to attempt anything other than getting the player working. The question was of academic interest only.
Nick.

[Boater Sam]

Is that mains voltage selector on the correct setting for your supply?

[SurreyNick]

No it's not Boater Sam. You are as eagle-eyed as Nuvistor, who spotted it too
Nick

[SurreyNick]

I managed to get a New Old Stock BSR-X5M cartridge with stylus and mounting clip (pics attached). I don't know how well is has been stored over the years but at first glance it looks clean and bright with no tarnishing to the metal. Is it safe to assume it will be OK or should I subject it to some sort of testing first?

Nick.

[D_S_J_R]

Ok, you're done...

I was going to suggest looking out for an ORIGINAL Ronette Stereo 105. I've got one and it does sound great at 6 - 8g tracking... Modern reproductions aren't too good in my experience.

The BSR you've bought is great too, so don't worry. If you can't carefully work around the cartridge weight vs tracking weight differences, you may need some blue-Tac ballast perhaps. I don't know the deck at all so can't offer anything other than to check for dried out grease and lubrication of the motor, idler and main bearing bearings...

[Edward Huggins]

Originally Posted by SurreyNick

I managed to get a New Old Stock BSR-X5M cartridge with stylus and mounting clip (pics attached). I don't know how well is has been stored over the years but at first glance it looks clean and bright with no tarnishing to the metal. Is it safe to assume it will be OK or should I subject it to some sort of testing first?

You were lucky to source this. The best way to test this is to fix it in and play it.

I notice it has a high compliance stylus which would be great in the right arm, but I'm still not too sure how that old Plessey arm will cope with it. As I have said before, you are trying to defeat the Laws of Physics by trying to make this something it can never be.

[SurreyNick]

Thanks. Fingers crossed and all that.

According to the manual I obtained for this deck it is possible to adjust the tracking weight....

Adjustment Of Stylus Pressure
"This may be carried out with a thin 4BA spanner on the hexagon C. Turning the hexagon clockwise (upwards) decreases the stylus pressure on the record and vice-versa.
The recommended pressure measured at the stylus is 15-18 grammes with the 78 r.p.m. head and 11-13 grammes with the 33/45 r.p.m. head."

I don't know if I can get the weight low enough for the BSR-X5M (it's much less than the existing cartridge), but at least I can give it a go.

[Audio1950]

Originally Posted by SurreyNick

According to the manual I obtained for this deck it is possible to adjust the tracking weight....
I don't know if I can get the weight low enough for the BSR-X5M (it's much less than the existing cartridge), but at least I can give it a go.

That's good news! You should be able to fix the new cartridge into the headshell
using the single screw hole that was used for the old one. You will probably be able to get the weight down to around the 5 gram mark, but my concern is that there will not be enough weight in the arm to trip the knock-off mechanism at the end of the record, and the arm will stick at that point. We'll see......