Dynatron SRX20

[technotel]

Could anyone help me identify this cassette deck used in my SRX20 Dynatron.
And where I can get circuit diagram? The issue I have is when play key pressed there is loud clicking from speakers. If I press the record key several times which moves the record/playback slide switch, the clicking goes for a while. I suspect the slide switch??
Many thanks for any help.

[nickdoofah]

It looks like a generic Japanese deck made to simply drop into music centres of the time! A good squirt of Servisol 10 switch cleaner should sort it out! Don't forget replace the belts too - An easy job on these well made cassette decks.

[Nuvistor]

It’s possibly a Philips deck, have you tried cleaning the switch, the switches tarnishing on many cassette decks was a problem.
Test the cleaning fluid on the plastic switch where it can cause no damage before cleaning the switch.

[ben]

The cassette decks were often the weak spot on music centres of this era. Typically a shoebox piano key type mech, with single motor and idler drive for the spooling. Nevertheless, their simplicity usually makes for a cheap reliable fix. Shot of switch cleaner int the slider switch, work it back and forth about 30 times, resurface idler tyres with fine sandpaper, new belt and you should be okay!

[Edward Huggins]

To avoid any confusion, this is definately not a Philips deck. Wherever Philips cassette mechanisms are used on Dynatrons, they are easily recognisable from their original "seperates" version.

[technotel]

Originally Posted by nickdoofah

It looks like a generic Japanese deck made to simply drop into music centres of the time! A good squirt of Servisol 10 switch cleaner should sort it out! Don't forget replace the belts too - An easy job on these well made cassette decks.

Thanks Nick but it does not look Japanese!! Looks very familiar, I think its a Philips. Its not a "drop in" unit. Its been taken out of main unit for ease of working on. Does not just drop in and plug into main amp. Many years ago I worked at a dealership that sold high end equipment such as Roberts,Dynatron,B&O,Hacker etc. I was service engineer and the chassis does look Philips. I dont have servisol. Can I use WD40?
Many thanks
technotel

[technotel]

Thanks guys for all your tips here. So general consensus is the record/Playback slide switch? As a long term fix. I was thinking of removing the switch and bridging the appropriate areas on pcb. Of cause I would keep the slide switch to restore it back into the deck if I ever sold it. Do you think however, the cleaning of it will solve the problem long term or at least a few yrs?
thanks again all

[technotel]

I have various faults with the whole unit inc. Garrard S35B arm does not rest and shut off after it has returned, it sets down onto record again. However. I read from another thread on here that one needs to select "auto" function and pause before releasing, and then it will shut off after playing record and returning to rest??
Also no FM on this SRX20
technotel

[Edward Huggins]

Is the overarm on the Garrard deck fully pushed down and seated? You say no FM so assume there is AM. Clean the waveband switch contacts. WD40 is not a substitute for Servisol.

[technotel]

Thanks Edward
I will try some WD40 So its not Philips deck. Any idea what it might be ? The components look typical of Philips, the transistors for instance and electrolytic caps all look typical of what I worked with when I was a tv engineer working on philips G8 and G11 chassis

Terry

ps: yes there is AM

[technotel]

Originally Posted by Edward Huggins

Is the overarm on the Garrard deck fully pushed down and seated? You say no FM so assume there is AM. Clean the waveband switch contacts. WD40 is not a substitute for Servisol.

Excuse my ignorance Edward but what is the overarm?
thanks
Terry

[Michael Maurice]

As far as I’m aware, the Garrard S35B does not use the over arm to detect the presence of records. That deck will need to be stripped, cleaned and relubricated.

Do NOT under any circumstances use WD40 anywhere in your radiogram. It is not a switchg cleaner, nor is it a lubricant.

[technotel]

Arhhh ok now I know what overarm is. Thanks Michael. No this player is a single record only. I will buy some servisol 10 to clean the switches. I did read somewhere that if the start lever is moved over to the "auto" position and let go. The arm will reach centre and return but not stop, but repeat and set down on record again. If you want it to stop on return? You pull lever over to "auto" and hold it there a few seconds before releasing and it stops after playing the record ? I will try this, maybe no fault after all ??
Terry

[Michael Maurice]

Its a 35SB which looks like the belt driven version of the SP25.

What should happen is that you move the start lever to auto and let go, the lever should remain there and move back to the manual setting on its own. If the lever moves straight back to manual it means that the mechanism underneath has seized. You really need to strip it, clean it all up and relubricate.

[Michael Maurice]

Further to my post above, turn the deck over to you have the underside up,

Now operate the start lever, you will see a protrusion from that lever which goes into a cutout of another lever which has a spring attached.

What should happen is that that lever should move to keep the start lever in the auto position until the cycle has started.

Often that lever seizes on its pivot. Remove the circlip and using heat from a hair dryer, warn the pivot up until the lever moves, then lift it up and remove it. Once it has cooled, Clean the pivot and the lever of old grease, pit a tiny amount of fresh grease on it and reassemble.

That will cure the auto function fault.

[technotel]

Michael
Thank you so much for this great information.
Terry

[technotel]

Hi again guys
further to various faults I have with my dynatron srx20 chassis. Can anyone advise what lamps attached are rating etc and where I can obtain? They are blown. I measured the voltage to them and meter reading was 2.5v ac. Is that right?

Also re no FM. I have discovered that there is no 15.4volts that feeds the FM stage. further investigation reveals that TR261 has no emitter volts. readings on the transistor is B=15.77v E= 0v C= 27.26v there is a zenner connected to the base to ground BZX79C16. Must this voltage be exactly 16v ? I have not checked the zenner or c262 220micrfarad elec or r262 1.5k
I have attached images of the lamps and circuit around tr261.
Any advise would be greatly appreciated. My reading of circuit diagrams is a bit rusty since I stopped being a tv engineer back in the early 90's.
I really like to also find schematic for cassette deck attached? I would be able to discover the voltage and wattage of the vu lamps?
Again thank you for all your help on this great site for vintage audio knowledge

[DMcMahon]

Have you tried disconnecting the load off the +15.4 volts line (leaving R261 connected) to see if you then get a good output from the emitter.

Zener clamping voltage at the base of 15.77 volts should be OK but would be good to check R261 and the transistor junctions if still no output.

I see previously people have provided you with various pages from the Service Manual, do you have the complete manual ?

I now see that with the FM switch off the load may be removed from the +15.4V

[technotel]

DMcMahon sorry for missing your reply and thanks. I have not disconnected anything yet but isn't de selecting FM button which effectively cuts the 15.4v supply to the FM stage, the same thing? I have all the components now fro cpc and will pull out old to test. I will get back with what I findings

[technotel]

Originally Posted by DMcMahon

I see previously people have provided you with various pages from the Service Manual, do you have the complete manual ?

DMcMahon yes lots of good literature here but nothing on the cassette deck. I have issues here as well, trying to find out what wattage the blown vu lamps are for a start and left ch playback lower volume Than right ch.
regards
technotel