I've inherited a Westminster record player
It's a Curry's own brand (Fidelity ?) 2 valve amp & is basic but seems to be worth getting to work properly.
Currently low volume & too much hum.
There has been some work done allegedly by a "proper" Radio/TV shop a couple of years back that included fitting a 3 wire mains cable & then earthing the deck with the earth wire in the lead !.
That's the first thing to go & will prob's sort most of the hum as well
My initial question is..........how can you check if the O/P of the cartridge is correct ?
I've had a voltmeter on the tonearms output connectors on the deck & it there is certainly an emf there that seems to hit around 500mv when playing a record but I know it's not as simple as that sadly
Checking by substitution would be the obvious way but I don't have one to sub
The cartridge is a BSR X3M that looks original & I understand is just about impossible to get these days.
I imagine it will need a high O/P cartridge with the basic low gain amp that's fitted
It's been a while since I looked at anything like this but "an amp is an amp" as they say, or are they any "quirks" to these little amps that can give this sort of issue ?
Any ideas appreciated
Dick.
Apart the stylus replacement above a whole new cartridge can be bought for under £ 30 -
https://www.jukebox-revival.eu/staging/a...r-x3m.html
It's a ceramic/piezoelectric/crystal cartridge, so unlikely to fail.
Regarding the amplifier, it's likely to be similar to a Fidelity HF31 or Dansette Junior . These were all similar - you need to replace the cartridge isolating caps with Y-rated ones, replace any wax caps and check all resistor values and all electrolytics' ESR.
Be warned! The chassis on these are sometimes not isolated and can be live.
Typical circuits:
[
attachment=14530][
attachment=14531]
Adam
Thanks for your reply, the stylus is fine & I'm sorted with a cartridge now.
Nick
Thanks for the links & cct
I've seen/heard of many of these "carts" failing especially after long periods of storage as the moisture gets at them as you know it's not easy to get accurate O/P results with a DMM on these things ......"charge coupled" ?
I've ordered a replacement from "Juke box" .......seems like an interesting place & it will get me a known good cart that I can start with.
I did a check check on the "dropper" resistor while I was looking around & got 105 ohms so that would seem OK
The cct does look like the one I have here, I'll draw it out later when I get some time
Question.................... to earth the deck to the mains lead or not ? (3 core lead fitted by previous owner)
Cheers
Dick.
As I understand it, and I've been repairing electronic items for 45 years now, a three core mains lead should never be used in any apparatus using 'U' series valves (i.e. sets commonly referred to as 'live chassis' models) It's also important to ensure that the Neutral side of the mains is connected to the common negative line (usually the amplifier metalwork) in circuits such as the two shown. The isolating capacitors shown in those circuits should be replaced with 'Y' types, as Nick says. If the mains lead is the old twin 'bell wire' type, it should be replaced with a modern double insulated type. (BTW, despite what I've just said about never using a 3-core mains lead I've just noticed tha both those circuits show that such a lead is fitted, with the earth lead connected to the record deck metalwork.
It was common enough to earth the deck of a gram like this. If the earth was OK this would protect the user if something went wrong and mains found its way on to exposed metalwork. I'd always use an RCD with kit like this.
Old Sparky
That would also be my understanding of this.
When new I would have presumed this was supplied with a 2 wire mains lead............................. I can however see the logic that has been applied by the person who fitted the "new" mains lead
The caps C2 & C7 are being relied upon for protection which I'm unsure is valid enough.
My reaction is to have things the way it was supplied (I'm guessing early/mid sixties )
Interesting...................... I need to check to see if the ccts linked by Nick are indeed "original" ................. hope I'm not opening a "can of worms" as they say
Dick.
Another point is that these cartridges are famed for trashing vinyl. I wouldn't play anything you value on this
You can also always fit a small 1:1 isolating transformer...
Jeffrey
Agreed................................... our bungalow supply is PME with up to date wiring/protection so there would be no extra protection given by a plug in rcd.
A bit of "belt & braces" won't do any harm though
Dick.
Nick
Yeah, this thing is just going to be for playing 45's mostly bought at car boot sales.
I went down the "hi fi" road in the late 70's to 90's & spent a lot of money one way & another but eventually accepted that cd's are a valid music source eventually & sold the "good" gear & most all of the albums
Almost all my music is digitally stored these days with maybe 30 or so albums left that I can play on a "retro" player that I bought for "SWMOAT" that I will keep for the "shed" when I get this box playing properly
Dick.