Mirage 88 PLL / VCO problem? NO RX or TX same as GALAXY 88

Pioneer621 · Post by **Pioneer621** » Wednesday 26th Jul 2006, 11:15

Radio. Mirage 88
Problem. don't seem to be locking on any frequency's

Hi, I have a Mirage 88, same radio as the GALAXY 88HL radio's. It powers on ok, but has no receive in AM - USB - LSB, but in FM I can here normal static only. When I transmit, the light goes red but no output. When I change the band selector it does not do anything, the frequency counter reads 26.055 no matter what band its set to. The frequency counter seems to work fine just the radio is generating the same frequency to the counters input. When I received this radio, after inspection I found it was missing an RX switching transistor TR37 2SC945, as well as the RF PRE-DRIVER transistor TR45 2SC1973. I replaced these two transistors, I noticed the Pre DRIVER transistor, when I key up it gets fairly hot. I checked both finals and they seem to be ok as well as the driver.

I also see This radio had its frequency coverage exspanded, by pluging in the JUMPER (J3) & removing the wire on the solder side of the small PC BOARD (EPT00441OZ). If that helps any.

I checked the frequency on the 10.240 crystal and it was reading 10.239, so its not to far off. I also checked the frequency on another crystal and it was 10.695mhz I can't remember which crystal it was though. Now I have never owned an export type radio so I am not really sure where to check things out, theres a bit more stuff in there compared to a Cobra 29 LTD. I am still learning so I figure I would ask people with more experience in these radios to maybe give me an idea where to check for the problems. Seems like the problems are in the PLL / VCO area of the radio, so where should I check for propper frequency / voltage pionts? Could it possibly be very badly miss-aligned? Has anyone seen this problem before in these radios? I Hope I can get some info on this as it looks like a nice radio, If no one has any info I will keep checking stuff out and see if I can fix it myself, its fun trying to fix them up!

I have a B & K precision frequency counter that is pretty accurate, as well as an Audio Frequency (AF) watter meter & of course watt / modulation / SWR meters, as well as tuning tools & dummy loads. Thats about it for the test gear at the moment. Should be enough to get the radio going and tune it up pretty good.

Ok, hope I covered everything, if not I will post back. I will continue working on it with the information I do have, but still hope sombody here may be able to help me out with it or give me some advise on where to begin looking. I have some other radios to work on so I may put this one on the side for now.

Thanks for your time looking and hope to see some info soon, Again Thank You. Kyle.

http://www.youtube.com/user/TheDefpom · Post by **The Defpom** » Wednesday 26th Jul 2006, 15:53

Hi,
A good way of identifying where a problem may be is to do an alignment, any odd readings at the test points can help guide you to an area that is faulty.

Rick · Post by **Rick** » Thursday 27th Jul 2006, 3:11

I sound like you have lost some volts.
Check the voltage at the PPL pin1 it should be about 8 to 8.5 volts also check Tr36, Tr37 Tr38. Tr41 should read (Base 12.3 to 12.6 V Emitter DC input voltage 13.8 Collector 8.3 to 8.5). Lets us know how you get no.

Rick.

Pioneer621 · Post by **Pioneer621** » Friday 13th Oct 2006, 16:43

Hello again, I have not been on here in a little while. I really appreciate your reply's to my post! Thank You very much Defpom! And Thank You very much Rick! Your replys are very helpful. I have not really had time to trouble shoot that radio, so its basicly been sitting on the shelf. It may be there a while, but I definately want to repair it sooner or later. Anyway Thanks Again. Kyle