Solid State 9 2 Wave Band - Satellite Electronics LTD

[mediaseller]

Hi.

I am restoring one of these currently, and can't find a circuit diagram anywhere.

I've tried www.service-data.com and radio museum.

Can anyone help, please?

Thanks in anticipation.

[paulsherwin]

It looks like a pretty typical late 60s Hong Kong no-name radio. I doubt if you'll find service data for it, but it's likely to be a standard conservative superhet design. The audio output stage is clearly transformer coupled.

I actually think it looks quite attractive in a cheap 'n' cheerful sort of way.

[Graham G3ZVT]

Further to Paul's reply, the schematic won't be a million miles different from this typical 6 PNP transistor, -9 volt supply rail, Far Eastern, 1960s set.

[paulsherwin]

The OP's set looks as if it may use silicon NPN transistors with a +ve supply rail - easy enough to work out anyway. It's post 1967 and pre 1978, probably around 1970.

[mediaseller]

Originally Posted by paulsherwin

The OP's set looks as if it may use silicon NPN transistors with a +ve supply rail - easy enough to work out anyway. It's post 1967 and pre 1978, probably around 1970.

Hi.

Thanks. Yes, they are silicon pudding bowl transistors.

[mediaseller]

Originally Posted by Graham G3ZVT

Further to Paul's reply, the schematic won't be a million miles different from this typical 6 PNP transistor, -9 volt supply rail, Far Eastern, 1960s set.

Thanks Graham.

[mediaseller]

Originally Posted by paulsherwin

The OP's set looks as if it may use silicon NPN transistors with a +ve supply rail - easy enough to work out anyway. It's post 1967 and pre 1978, probably around 1970.

Thanks, Paul.

The variable capacitor is a bit scratchy, so I cleaned the spindle end. I'll try it out again tonight.

[mediaseller]

Originally Posted by Graham G3ZVT

Further to Paul's reply, the schematic won't be a million miles different from this typical 6 PNP transistor, -9 volt supply rail, Far Eastern, 1960s set.

Thanks for the drawing, Graham.

[Graham G3ZVT]

R.M. says Number of Transistors = 9. The power of suggestion.

[paulsherwin]

It may be using transistors as diodes to bump up the transistor count, a very common HK dodge in the 60s. Sometimes manufacturers just lied though.

[G6Tanuki]

Yes, a transistor with B and C strapped together to work as the detector, and another similarly wired in the Base bias network of the output transistors....

Always good to bump up the transistor boast count.

At least a diode wired transistor in the output stage bias network was a serious attempt, properly done it could reduce the overall standing current in the output pair and compensate for ageing batteries where the voltage was sagging.

[mediaseller]

Thanks all for your suggestions.

I was at least successful in the end with the help of some responders.

Replaced the tantalum cap with a parallel pair to get the right value. I went over the board, resoldering poor joints, and used contact cleaner on the VC.

After a quick basic alignment, it works well.

Thanks again.

[Herald1360]

An interesting mix of TO72, plastic and TO5(39?) transistors if nothing else!

I wonder if the solder bridge between the IF cans was a design feature or a quick fix production bodge?

[paulsherwin]

A lot of HK radios from that era used TO5/39 output transistors despite their large size, often covered with coloured plastic.

[Hybrid tellies]

I am glad you got this radio working. Its a very attractive looking radio and a good example of what was a very popular style of small HK radio from the late 1960's.

I agree with all the comments said about the transistor count using transistors with a leg snipped as diodes typically for the detector and output bias.