Dynatron amplifier module

[Keith J]

I have a Garrard Dynatron SP25 Mk4 system. One of the speakers is affected by interference, which according to my local repair cafe electronics advisor, is caused by a faulty circuit board - Assy 0112. (as pictured). However he has been unable to identify or source the part we need. He is confident that the speakers are in working order and it’s this faulty module which is the problem. Can anyone identify this part and maybe suggest where I can obtain one?

[Cobaltblue]

Hi and welcome to the forum.

The picture shows a power amp module possibly from an SX series Dynatron.

The Garrard bit is the manufacturer of the record deck.

There doesn't seem to be anything made of unobtanium on the amplifier and noise is likely to come from a faulty component or joint.

Or is there something specific on that board the repair café could not source?

The little jelly bean transistor (the one with the shiny black top) or the preset potentiometer for example are possible noise sources (other possible noise sources are present).

Cheers

Mike T

[FIXITNOW]

some info on Amp here that may help guy from repair cafe ..https://andydoz.blogspot.com/2018/07/sam-and-queen-anne-dynatron-1275a-series.html

and service data from this group can be got here
https://www.service-data.com/section.php/10375/1/1275-series

[Edward Huggins]

Can the OP provide the model number of this Dynatron? The SP25 Mk 4 is just the name of the Garrard deck. The speakers are liable to be just fine. If the Module can be positively identified, it might be possible for it to be sent to a Member of this Forum to measure, test and repair. All the components are discrete. From the photo I can't tell what the output trannies are, they might be Newmarket?

[Station X]

The speakers can be tested by swopping them over between channels. If the fault moves with the speaker it's a speaker fault.

[Michael Maurice]

I've worked on loads of these, but they have all failed completely usually with the fuse blown. The output transistors are BD130Y.

if you know what you're doing, you can swap the modules over to see if the interfence moves with the faulty module.

[Keith J]

Thanks for all your replies, very helpful and informative. Our Tuner/Amp is a 1275A and the tape section is CR102 D. As I know absolutely nothing about electronics, I will go back to the repair cafe, armed with your suggestions and hope that the guy there can make some progress. Incidentally Fixitnow, Doz' blog was highly amusing.

[Rcarrington]

Bad contacts on the turntable head can cause nuisance noise; where the stylus cartridge is connected to the wires that come through the arm. IF yours is like mine, the cartridge wires are soldered to the arm wires, so whilst changing Stylus's its easy to damage these connections.
I've recently rebuilt both amps, the same as yours. All the components, or completely compatible alternatives, are available.
There's plenty of info on this site about how to do this.

[Michael Maurice]

Originally Posted by Keith J

Thanks for all your replies, very helpful and informative. Our Tuner/Amp is a 1275A and the tape section is CR102 D. As I know absolutely nothing about electronics, I will go back to the repair cafe, armed with your suggestions and hope that the guy there can make some progress. Incidentally Fixitnow, Doz' blog was highly amusing.

If its beyond the techies at the repair cafe you can always send the modules to me for testing and if necessary repair.