Cobra 2000 GTL in bad shape

[Smokinone]

I just got around to opening up my late father in laws Cobra 2000. I think it may be more of a project than I can handle. It has a UFO Super Star 1604 installed. The PLL is missing and a lot of the area around the PLL area is void of parts. Looks like a 10 turn pot for the clarifier, the protection diodes for the driver and final have bee kinda cut loose and dangling. Actually there are quite a few wires that are either pulled or cut loose. I haven't zoomed in and taken pictures of any of this yet. I'm sure it will need to be re-capped. I will attach some photos of the solder side of the board to show all or most of what's been done. I think either the final or driver may be missing as well. I may have some, I will have to look at the parts list. That would be the last thing to do I think at this stage anyway.

I would like to get this back to as stock as possible. The PLL is missing in action, but I think I have a MB8719 or RCI8719 in my parts bin.

Should I give it a try and do a wholesale removal of the VFO, and then reinstall the missing parts from the parts list.

Or, see if I can find a guy who can put it back to stock for me and be sure it's put back right.

Or, give it a whirl, and if I can't make it better, maybe I won't make it worse.




I really don't know what's supposed to be here or not. I do have a 148GTL, I wonder if that's close enough to use as a guide to get it put back right after getting all the junk out.

I haven't plugged it in yet to see if it even powers up. Maybe I'll get brave tomorrow and bring it online with a dim bulb tester to see if it has any life at all.

I'd love to have it back up and running if not just for sentimental value.

 

[Holydvr]

If you need any pictures let me know. I dont get back home until Sunday though. I have a couple of them.

 

[Smokinone]

Well, I have it plugged in after a start with the dim bulb. All is well as far as no shorts or high current draw.

knobs are off as you couldn't see any of the front panel for the grime and dirt. Been sitting in his shop for 20+ years. Still not a thorough cleaning as yet.



It works. I'm astonished. It runs up and down the channels with the UFO, and the counter on the Cobra tracks it. Low output on SSB at about 8-9 watts peak on the WM-1. AM is better DK 5 and about a little over 10 peak. This unit has the 1306/1969 combination for driver and final.

solder side of driver/final





I'll look into all that as I get time. I'll take some readings from the service manual and see where it sits. The clarifier seems to work backwards ie: goes down with a clockwise turn, and up with a counter clockwise turn. Maybe a switch on the wiper will cure this.

Anyway, I'm happy that it works as well as it does, I was thinking it was much worse. I think I would still like to just get it back stock without all the added extra nonsense, but we'll see how it goes.

This is L4, looks a little out of the can???

 

[Smokinone]

I think I'm going to leave this channel mod, SUPER STAR 1604 in place as it does seem to work. I have made contact on the AM side on 19.

Would anyone happen to have a copy of the install manual for the SUPER STAR 1604 that I could get a scan of? Seems to default to 27.115 when powered down, that also is the PRI freq. Just wondering if it can be reset, or if it's suppose to have a memory for last channel.

My direction now is to re-cap the radio, and attempt an alignment to see if I can get a little better performance from the SSB power. It may have been broad-banded to the degree of less power or equal power across the spectrum. That all remains to be seen when I start the alignment.

Question: The MV13YH that is disconnected from the final seems to test good, at least like a diode would test. Should I put this back in place before I get to the driver and final bias adjustments, or even transmit? I really can't think of a reason it would be out of circuit. It is a little hard for me to see where on the board it goes back into at this point.

Also, would there be any advantage to up the power supply cap from 4700uf to say a 10000uf capacitor? I have found some that replace C172 with a 2200uf.

Thanks for any help in this matter. I know I ask a lot of questions, sorry.

 

[TM86]

I pulled these pdf's off of transmission1 in the last five minutes or so, I hope it's what you're looking for in the way of documentation.

 

[Smokinone]

I pulled these pdf's off of transmission1 in the last five minutes or so, I hope it's what you're looking for in the way of documentation.

That's perfect! Thanks very much. I didn't come up with anything when I did a search.

I'm going to start a re-cap here soon. I need to clear my desk first. It's a little more difficult wrestling this base around VS a mobile unit, especially with the UFO box hanging off to the side.

Thanks again.

 

[TM86]

You're welcome. For some reason I've been able to find some obscure things on the interwebz lately. Might as well share.

 

[Smokinone]

If you need any pictures let me know. I dont get back home until Sunday though. I have a couple of them.

Thanks. I could use a pic of the final/driver area to see where the protection diodes go. I have a Taiwan made 2000. I opened up my Philippine 148GTL, but it has a different board evidently.

I'm not in any rush really, I still have to get to re-capping this thing.

Thank you.

 

[Smokinone]

Thanks. I could use a pic of the final/driver area to see where the protection diodes go. I have a Taiwan made 2000. I opened up my Philippine 148GTL, but it has a different board evidently.

I'm not in any rush really, I still have to get to re-capping this thing.

Thank you.

I think I have it. I watched some videos, and checked placement with the schematic, and now I believe I have it back in circuit correctly.



Thanks

 

[Bombardier]

If you need any pictures let me know. I dont get back home until Sunday though. I have a couple of them.

Any pictures are appreciated, when you get time, this project won't start till next week. Thanks for the offer.