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The elusive YD1022...

Chevboy0167

Chevboy0167

Well-Known Member
Apr 5, 2017
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Good day gents and ladies. I have a 2006 Cobra 25LTD with the YD1022 audio ic that has suffered the overheating crack of doom. This is a fleabay rig I got on the cheap. Here is where it gets interesting.... the plastic screw that holds the ic to the chassis has broken. No nut and stub left.... sheared off. Head of screw was only thing in the hole. Of course she overheated at some time and let the smoke out in to the wild. I read bad things on the net about none available. So... anybody have info or a lead on who may have some? Or if any members would be willing to part with one? Thanks kindly.
 

Hey Robb. Yeah, I have a tried a few sites like that. No go. I also found a site that shows the conversion I believe to the TA7222 and the support components???? Gonna take some spec sheet looking at though for proper pin out.

Not a huge loss if if don't work. Got radio cheap enough that it could be used for parts. I just like to bring em back alive if the cosmetics are good. This one is good looking. Had to put in a new 1N4004, remove cracked audio ic and fired it up. Everything else works great.
 
Be cautious after the chip gets changed. I would suspect a bad audio transformer.

The quickest test I know is to take an external-speaker cord that's cut off, stripped and tinned at one end. Plug it into the external jack of a radio that's receiving properly with the volume set fairly low. Gator-clip the stripped ends of the cord to ground and the input pin of the transformer under test. With that radio powered down, of course. If the shorted audio chip is still in place, unsolder the audio-output pin from it first.

A working external speaker plugged into the second radio should sound okay. It's okay to turn up the volume once you get this lashup connected. If the receive audio sounds bad, or terribly weak that suggests a damaged audio transformer.

There is a blocking capacitor, usually between 330uf and 1000uf between the audio chip's output pin and the audio transformer. A damaged chip may have been caused by this cap going bad. This kind of part can internally "heal" itself and check okay on a meter, even if it was the cause of the problem to start with.

We ALWAYS replace this cap any time the audio power chip gets replaced.

Cheap insurance.

73
 
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Too many people have been unsuccessfully searching for a source for that rogue chip for years. Your only option is a parts radio like the 29 chrome or another 25 with the same chip. I don’t think converting to a TA7222AP is worth the effort. There are too many differences to contend with. For me it would be easier to just use the cases, bezel, knobs etc. on some beater 25 that works. If you’re going to do the conversion, besides schematics, you should have another 25 with a TA722AP for an additional comparative reference anyway. For those looking for an YD1022 datasheet, this is the only link that I know of. I would save that PDF to your archives. It seems that all the other links are dead ending.

YD1022 datasheet
 
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Looks like if I can find a cheap parts radio like the Cobra 18 WX ST or variant may have the YD. BUT... it also looks like they came with 2 flavors of audio IC also... I see a few on the bay but no internal pics and pricing looks to be $20 plus for just a used IC and then a dead radio laying around. May be my only choice though....
 
Ill look through my parts bin and parts radio pile and see if I have one. It’s pure stupid to change something like that especially to something that’s so hard to find. That 7222 part has been used forever, why not just keep using it?

I’ll let you know what I come up with.
 
They quit using the TA7222 because nobody made them any more.

The scraps we can buy in small quantities were not enough to feed the needs of a factory assembly line.

The YD part was what a supplier offered to the vendor, probably a low bid.

The data sheet for the YD1022 has a puzzling type. Shows a "+" input symbol for pin 3, and a "-" label on pin 2. But the sample circuit, and the radio schematic make it clear that these two labels are reversed. The "-" pin is where negative feedback is connected, and the "+" is the signal input.

The reverse of what they show.

Go figure. It's a Dilbert universe.

73
 
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