Restoration of HMV STEREO 666 (1976)

[kaushik]

Love vintage restorations ..carry on the good work

Here is a picture of the board. The diodes (the left-most two and the right-most two) used here are very strange looking. These diodes are in TO-1 package. This type of package is used generally by transistors. I have never seen any diodes using this package....

I was very confused about the value of the Q1 and Q2 transistors. The marking of Q1 was gone, and marking of Q2 was very fed. rigorous editing of the close-up picture of Q2 revealed its marking.

Here is a close picture of diode. The picture was taken during the testing of the circuit. The diodes have very faint markings on it.

Specifications of the diode are as follows -

Diode Name = OR23
Forward Bias Voltage (Vf) @1mA = 168 mV
Forward Resistance = 900 Kilo-ohm
Maximum Current Handled (I-max) = 1A

The value of Vf is a very strange figure. Such a low value!!!!!!!!!!!!!! A good Schottky Diode have Vf at about 215 mV. Dont know by what the diode is made up of, whether it is a Schottky or a germanium diode. Another strange phenomenon I noticed that Reverse resistance of the diode is as same as the forward resistance, whereas reverse resistance should be 100 or 1000 times greater than forward resistance of a healthy diode. My question is, Based on the above-mentioned specifications, is there any Schottky replacement available?

 

[BHARATH B A]

Hello Sir I too also having the same HMV Stereo 666 record player I too also need to restore it I need your help sir. Previously some body has mis tuned the bias presets, please share me the amplifier board images and close-up shot of three presets. Please.
Thank You.

 

[dr.partha]

Though it is 5 long years have passed. But I found this thread today. It was a very nice and informative thread. As I also have restored this player, this thread is very much relevant for me. I must mention that FM Reubensm has helped me a lot in this restoration.
Anyway, a very nice job done indeed though I missed the active discussion in those days.
Regards,

 

[dr.partha]

And a quick question ( if you are still reading this thread): do you possess the original HMV speakers? If yes, would you please tell me its specifications (size and impedance are only required)?
I'm planning to buy its paired boxes. Hence I need the size and impedance. Is it a 6 inch speaker or 8 inch?

 

[reubensm]

And a quick question ( if you are still reading this thread): do you possess the original HMV speakers? If yes, would you please tell me its specifications (size and impedance are only required)?
I'm planning to buy its paired boxes. Hence I need the size and impedance. Is it a 6 inch speaker or 8 inch?

You may want to have a look at the video by our FM Anirban on Youtube. There are a couple of HMV speakers (assuming these are in use) on either side of the rack.

 

[dr.partha]

Thanks.
It's really nice warm sound. But can't capture the size of the speakers. May be It's 8inch.
However I'm going to Chandni Chawck market this Thursday to meet Mussha bhai. My first preference is to collect a pair of AD161 162 (if available). I will ask him regarding the speakers and if available, will buy a pair.