Hello All,

I'm new to the forum and have come seeking assistance to repair this Astor car radio.
I have a reasonable knowledge of electronics, but limited specific knowledge of vintage radio.

The only markings I can see on the main board that may identify the model is "CD 214A"
I have searched the forum and only came up with one similar model being repaired http://vintage-radio.com.au/default.asp?f=1&th=1330
I downloaded the repair manuals posted in that thread but thus far haven't really been able to precisely nail down the correct model.

It does not have a 3.5mm jack for current measurement as far as I can see. (Was this accessible externally or only once the case is open?)

I know I should not have powered it up, but I couldn't help myself....
I get static from the speaker - and am unable to alter the volume.
I cannot tune to any radio stations using a period correct coat hanger antenna.

I'm guessing any electrolytic caps will need replacing, is this where I should start?

Here are some pics, many thanks for any assistance offered.

There should be a small letter stamped somewhere on the case. That won’t necessarily identify the specific model, but it is a start.

How many transistors are there? The two AD149’s are not original as they would normally be AT1138’s. I can also see an Anodeon transistor which are reputedly unreliable.

The set is also riddled with Ducon Redcaps which can turn into resistors (the ceramic capacitors with the red tip on the top). Replace them and the set might actually work.

A service manual or at very least a schematic will be available once you can identify the model.

Thanks for your reply.

I can see 8 transistors. On the main board there are 5x TO-92 style (if they used that terminology then?) and 1x that's like a TO-18 type case.
On the upper board are 2x more of the TO-18 style.
I'm not sure which is the Anodeon. Does it look like a regular transistor, or am I not recognising it because they may look different?

Interesting you say the AD149's have been replaced.... It's never encouraging when someone else has been there before....

The only stamping on the case is:



Does this reveal any worthwhile info?

Noted re the Redcaps. I think I'll start by testing individual components, starting with the caps.

Ahhh, is this the Anodeon?
If so, the transistor count is 9.

The Anodean transistors are the little black silicon ones on the main board. The transistors are Astors own made by their Anodean picture tube/components/semi-conducted division at Huntingdale in Melbourne. The transistor types usually have a “AT” prefix. The red polyester “Anocaps” are also made by Anodean.

The AD149 power transistors can be used as a direct replacement for AT1138.

The letter “L” stamped on the chassis I believe indicates the model/chassis series as the same units are are used in the manually tuned versions.

If you can identify the transistor types it may help with finding a schematic.

Many of the non waxed paper caps of that era did not leak like the waxed paper ones of old. But there were some like the 3/8" by 1/2" axials, that were not inspiring and cracked jackets & often that failure shorted them.

With the heat and other factors, the electrolytic caps, commonly used for inter stage coupling would "dry out" as well as lose polarity (form) as well as capacity the later on its own, causing a loss of volume.

Thanks again for your replies.

When trying to read the numbers on the transistors, I found two more hiding under the sheetmetal of the pushbutton assembly, so that makes 10. Or 12 if you count the pair of AD149's
Among them are:

321OH
321OJ
321OK
321OL
327IA

I might start by searching for equivalents and replace these if they are know to be suspect.

Closeup example pic showing 2x

Thank for the pictures.

It is starting to look close to being this model below:

https://www.radiomuseum.org/r/electronic_diamond_dot_pn_c20j.html

https://www.kevinchant.com/uploads/7/1/0/8/7108231/pn-c24j_mn-c24j.pdf

There are more goodies below that may assist you with the restoration:

https://www.radiomuseum.org/tubes/tube_at321.html

https://www.radiomuseum.org/tubes/tube_at327.html

https://www.kevinchant.com/uploads/7/1/0/8/7108231/anodeon_transistor_data_1969.pdf

Thanks again. I just found Kevin Chant's pages - what a great resource!

The schematic you posted for the 'pn-c24j_mn-c24j' appears to be the closest I have seen to the radio I have here. THANK YOU!

I will look through the other links also.

One thing not seen & will eventually need to happen, is to expose the printed circuits wiring side. As you will note in one of those Kevin Chant pdf's, is a number in the top corner of the board additional to what may be printed on its top.

Often, on many printed circuits, like a 1958 Philips I fixed by subbing a battery chewed one for an undamaged one; that number identifies a board appearing in this ones case, in several different models.

HMV also hade chassis numbers appearing in different containers.

Do be aware that with Astor. That facia with Chrysler on it is a separate entity to the radio chassis. This meaning it could have a Toyota, Ford or GMH, facia on that same model radio chassis. I fixed one for an XW Falcon like that.

Those little clear plastic Styroseal pF caps are reliable, but easily damaged by heat. Some disk ceramics were not that reliable.

Marc

Those are Anodeon silicon transistors and they are unreliable - much more so than the Ducon redcaps in my experience.
Everyone's experience is different, I've serviced lots of gear full of Ducon redcaps and I can't really recall ever having to change one.

I have a 1958 Philips transistor radio that's used regularly and it still has all its redcaps and original yellow Ducon electros. In fact, nothing has been replaced or touched in this radio except the battery and it is a very hot performer.

Those transistors look like they are all AT321s. Replace with BC547. Note the different lead pinout.

But PLEASE don't shotgun the thing. Track the fault(s) down and only then, if you see a trend developing (like 2 to 3 of the same type part bad in a row) should you consider replacing all of them. It's too easy otherwise to make a mistake that will be VERY hard to find.

I think you'll have to signal trace it to find the faulty circuit. You'd inject via a capacitor a modulated AM signal at the IF frequency and see if you can hear that. Start at the last IF stage, and then the next to the last IF stage and so on.

I'd check the resistors, as that style I see may have drifted to higher resistance. But I'd do the signal tracing to see if you can find a dead IF stage or such.

Logic suggests one starts with the power supply after checking for obvious faults. As noted the electrolytic cap leaks dries out, & looses polarity Often it is quicker to dump the lot.

With electrolytics you can measure capacity in much the same way as the non polarised ones. Noting that if you have one of those Chinese muti-function widgets that test lots of things. If the cap has charge it will kill it. The rest needs a reformer, that takes time.

I normally test leakage on NP caps with an insulation tester, albeit a reformer here starts at 25V and can be used as a low current power supply.

The moot point is that starting at the power & audio end is pretty much essential, as you will not hear any signal up front if the audio is dead unless you bypass it.

Marc

Hi BP.

How did you go with your Astor car radio?

I worked on a lot of these radios when I was an apprentice.
What I have noticed in your pictures is that the output stage has been incinerated some time in the past.
The two transformers on the right, one possibly the input choke, have had their former severely overheated.

One of the two 0R27 emitter resistors has burnt up, the other looks alright.

When I encountered these radios, they commonly fitted with 2N301 transistors as audio output transistors. We mostly fitted AD149's. They were popular at the time.

Your radio looks to be a 1970 model. I have never seen one with two little metal case transistors on the circuit board on the the swing-up cover I only saw one BC108 style transistor on the upper board.

From memory the last of the series had the T03 transistors riveted in.
The final model had a die-cast case with a drop in covers. Designed to be a dead ringer for the Astor in looks. Made by Philips?

Good luck.

Wayne.

I thought I'd come back and add closure to this post.

I sent the radio to Kevin Chant for repair. It's just returned from it's journey across the country and he's has done a wonderful job.

If you are struggling with an old Aussie car radio, send it to Kev, you will be pleased with the outcome.