believe I've found where the fault on the radio is, but I'm definitely no electrician. The component with the yellow coating contacted the little black / purple guy.

What is the little black / purple guy?

Does anyone have a recommendation on who'd be best to repair the radio cassette.

Jaguar XJS V6 4.0 1993 series 3

Cheers

 

arrannorth,

Well done on diagnosing that connection! I can't help you but I hope you get it sorted!

Just to clarify, the engine in your car isn't a V6, it's a straight 6. Also, there isn't an XJS referred to as a Series 3.

Good luck with the radio

Paul

 

Thanks Paul! Apologies, still learning 🤓

 

I'm not an electrician either but it looks like a diode.

 

The yellow thing looks like a battery such as used in computers to retain memory. I've never heard of one in a car radio, but that sure looks like one. Assuming it is, I'll bet the burned looking area is leakage from the battery. Very common in older computers. It may have done damage to the printed circuit board. If so, depending on the damage, it could be beyond economical repair.
The black component with a band looks like a diode, as others have stated.
EDIT: is there writing on the side of the yellow component? If so, what does it say?
Jon

 

I'm betting the metal tab up against the yellow thingie is a battery contact.
Yes, a battery would be logical to retain codes and settings.

 

These sure the same:https://a.co/d/cOVJpEK

 

What's the model number of the radio? If both model number and part number on on the sticker, please post both.

 

It's a Diode. Allows current to flow in one direction only. Common failure which will sometimes cause a failure in the now unprotected component like an Integrated circuit component. Look for a small square black cockroach looking item with its top blown off.
To test the diode, apply small voltage in one direction and then the other. Current should only flow in one direction.
The purple band indicates polarity. Important.

 

Wow, everyone thank you very much for your generosity in replying in such detail. After some more specific googling based on what you have all collectively suggested you're totally right. Volt meter, battery and pack of diodes are in the post . Will report back - and also on any other items blown.

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That round yellow item is most likely a capacitor, it can act like a battery.

"small square black cockroach looking item with its top blown off." You would have been a hoot in an electronics engineering class. I assume you mean blown integrated circuit chip.

BTW, I am a ChE, not an EE, so i am no expert on radios

Doug

 

You'll be pleased to know, no exploded cockroach looking things inside. ( AJ9250R model)

It does look like it's been repaired in the past - unless this wire is a standard feature... which I doubt haha!... the pictures are of the big on/off/volume dial.

that repair has undone itself, so plan is to replace the diode... (need to get it off the board to see what one it is...) and I'll reconnect that green wire... unless someone thinks that's a bad idea?




Took a break from work to open it up, but need to resume. Will continue with it later tonight.

Interested to read your thoughts.

 

I'll bet that wire is from the factory. They often do things like that until the next circuit board revision. That could be your whole issue.
Can you get a closeup picture of the yellow disc next to the diode? Curious to know if it is a battery or capacitor.
I looked to see if there was a repair manual or schematic for that model number, but found nothing.

 

it's definitely a battery! Sony 2032

I did give it a good Google too, but only way to find out what amp that diode is, is to take it off first which is proving a mission in its self.

I ran a voltmeter on it and it's allowing current both ways. Disregarding polarity. (I'm learning!)

Originally the Sony battery was leant over a bit and it was contacting the wire of the diode at the polarity purple side.

Cheers

 

& also the tape holding the green wire in place was definitely old. Yellowed up a fair bit. So the factory thought is likely correct!

 

Very likely the battery leaked. Be sure to clean that area thoroughly to get the residue off the board. That stuff eats circuit board traces.
I've never heard of a coin battery in a car radio before. Built-in obsolescence since they will fail eventually, eapecially in a harsh car interior environment. I checked a later model Jaguar radio I have, and it doesn't have one.
Jon

 

Thanks Jon, appreciate your input 👍

 

What a stupid idea, a battery in an object that needs a lot of work to get it out of the vehicle if it needs to be changed.

Its not like changing the battery in a garage door remote.

Did Lucas make the radio, also?

Doug

 

It was Alpine Electronics Inc, made in Japan.

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Exactly 🤣 and honestly the effort of taking the thing apart... absolutely not considered serviceable