ITT RC500 Radio Cassette Player

[Crackle]

Thanks for the comments guys.
I have done a few more checks, mostly double checking where I got to last night.
I have checked the following resistors whilst in circuit, R67 = 47R, R15 = 554k, R14 = 1.2k.
Voltages remeasured on T6, B = .71v, C = 5.37v E = .1v
I have checked the resistance of the aerial coils a-b = .4, c-d = .2, e-f = 2.4, g-h = .5
S2 contacts 17 18 19 20 all seem OK
I tested T6 with the diode test on the DMM just to confirm and those tests seemed to come out OK.

I think S2 contacts 21 22 23 24 will be the next to check.

I have had to dismantle the lever assembly to get access to the S2 contacts.
Any other suggestions most welcome.
Thanks

[Crackle]

I forgot to mention the IF is listed as 470kHz on the CRTS service manual.
I assumed my one would be the RC500 A LW as it was marked "Automatic" on the service manual image, whereas the image on the CRTS document is not.
The circuit looks the same.
This problem is looking more and more like the transistor, so I will try a substitution in its place.

Mike

[Crackle]

It was the transistor.
As luck would have it I had a couple of spare 2SC460 transistors from a previous repair of a similar radio.
So it looks like these types are prone to go noisy or leaky and fail, even though they appear to be OK on a cheap transistor tester.
Mike

[Murphyv310]

Good result Mike.
Often we discount that a transistor is the culprit and conversely we plump for the transistor without doing any checks. In your case having between 0.6 & 0.7v between B-E should have made the transistor conduct which it was with 0.1v above ground, so if all the feedback components, coils caps and switches were OK then replacing the transistor was the right decision, and proved to be the fault.

[Crackle]

I have got to take it apart again, I forgot to anchor the bare aerial wires down with wax to stop them vibrating and shorting where they shouldn't.

Mike

[Crackle]

All finished now.
The FM rf alignment was out by nearly 2MHz so a bit of tweaking had to be done. I found when I had finished that it was able to receive up to 106MHz but I will leave it at that. The lower frequencies are on station which is all I am worried about.
This is a well made solid cassette radio, with surprisingly good tonal quality from its 3 inch speaker. There is a strong carrying handle which slides up from the top rear of the case.

Here are some photos.
   
   
and here is another one in silver finish, which I got a few years ago.
   

Mike

[Terry]

I found when I had finished that it was able to receive up to 106MHz but I will leave it at that. are some photos.

The scale is only marked up to 104MHz which indicates that it was produced before the European FM band was extended from 105 to 108MHz.

[Crackle]

Yes, that's correct, the spec says 87.5 to 104MHz, however it is designed to go up to 105, at least that is what the upper alignment point is, at the far end of the scale.
I find the rewind and FF keys confusing, its because you are looking at the player backwards and the tape travels from right to left during playback. I find it easier to use and prefer it when the tape deck is horizontal and the tape goes from left to right like a conventional tape recorder.
Mike

[Terry]

Mike, that spec is wrong. When the UK FM Band was extended it its upper limit was originally 104.5MHz - not 104 - and subsequently extended slightly to 104.9, so the alignment instructions agree with that latter figure (with rounding).

[Refugee]

The deck might be based on the shoo box style model where they were commonly used laying flat.
I bet the pressings were the same with a different key mechanism on them.