SEA 222 SSB - Need help troubleshooting

[bigwalt]

I need help in troubleshooting my SEA 222. Anyone on this forum have tech experience with this radio?

I saw several posts by Fairbank56 on this subject. Eric - are you still on this forum??

[DaveJ]

I've had experience in radio's before but not the one your talking about, maybe i might be able to help, what is the problem?

[bigwalt]

I bought a used SEA222 SSB & auto Tuner for use on a 45' sailboat I'm restoring. The problem is that it is not functioning. It has a vacuum florscent alpha/numeric display that does not work - and does not seem to be receiving any signal. It is a PLL digital design. I've checked all the suppy voltages (5 VDC, 8VDC, 10 VDC) and they all seem to be functioning correctly. I'm a retired engineer with an EE background - and am hoping I can find someone on this forum who is a marine radio tech and knows this transciever. I did obtain the service manual for it - so have all the schematics and pcb layouts. There was a forum member - Fairbank56 - who was a radio tech, knew the SEA222 and had made several posts last year to help out someone else with troubleshooting the radio. I'm hoping I can get into contact with him - his first name was Eric

[DaveJ]

Sorry, the problem sounds more complicated than i can help you with. I'm an Avionics Tech, so have fixed aircraft radio/radar's, but have the item and the manual infront of me. Not being able to see either and having no knowledge of the item, i can only have a stab in the dark.

But at a guess, since the display is not working, and the display is driven by the digital PLL circuitry and the PPL circuitry can cause the lack of Rx and Tx. As it is used to drive the carrier frequency for the Tx function, and is used to strip the voice from the carrier frequency in the Rx function. this is where i would be looking.

Looking at all the components around it, looking for damage on the capacitors and resistors, checking their values (you might have to desolder them to get thier correct reading), which brings me to another point, check the solder joints, with age you can get dry solder joints which look fine, but don't accually join at all.

[bigwalt]

Dave - thanks for this feedback - it's kinda what I was thinking. I'll try to put the scope on the crystal oscillator to see if it's functioning or there is a problem there. I did look the pcb over for cold solder joints and other apparent damage but did not eyeball anything out of the ordinary. Hopefully I'll locate a tech (Fairbank56) who knows this radio and can steer me in right diagnostic direction.

[BTPost]

Look at the Processor Clock Input, if ok, then look a one of the Data lines going to the Display and watch it while the radio is Booting up. If you got data transitions, then look at the Power Supply Line that Feeds the VFD. Now that you have Audio Out, Check the PLL VFO Outputs and Reference Osc. for good output waveforms. If that all works, then Feed a signal into the Antenna on 2182.0 Khz.... This is the Default Startup Frequency.

[DaveJ]

I wasn't sure what test equipment you had, most people don't own a scope. You proberlly going to do it, but since you have the manual, after you get it working, i would go through all the test points and bias all your stages, and then the unit will Tx/Rx like new. I'm jealous.

Dave,

[stuartyh]

Hello Bigwalt

I think I am the first person which required help on the 222 on this net work since maybe a year or two ago.
Since that time and even long before that, I have been working on the SEA222 for maybe about 15years or more.
So therefore I maybe able to help (Sorry I have not visited this site for some time).
If you let me know exactly what your problem is then I may be of help.

Regards Jeff

[bigwalt]

Jeff:
Thanks for reply. The problem was no VFD display and it turned out to be the display driver chip. I replaced it and now it's working again. I'm still troubleshooting it (i bought it used for use on a 45' sailboat I am restoring). Right now I'm making a dummy load (see http://k4eaa.com/dummy.html) so I can check out the xmitter function.

pm me your email address so I can stay in touch with you if I run into any other problems. I am also hoping I can utilize the SEA222 while I'm sailing to contact some of my ham radio buddies.

Again - thanks for reply and offer to help

Walt

[stuartyh]

Ok Walt

Happy that you got that one going.
This is a very rugged Radio and it can tune from 1.6Mhz to 30MHz and will go on any frequency withing that range ( I have actually tried it) so tuning in the ham band is piece of cake and the nice thing about it is the antenna tuner (if you have one) will tune automatically on any frequency between 1.6MHz and 30MHz
So using it on for Radio Amateur purpose on your boat is not a problem.(Being an exHam PZ1DJ naturally I had to take through its paces)
Once again no probs there and hope you work out everything.
Regards
Jeff