Motorola Spectra does not receive

[scooter783]

I have a Spectra VHF 45 Watt radio that I have installed in my car. I initially had issues with the radio giving the fail001 error message, so I replaced all of the leaky caps. The radio functions great now with no error messages; however, I am unable to receive any transmissions. I connected my Icom and it was picking up the same channels that the Spectra was supposed to. I do have audio though, as the unit will beep and adjust volume. I'm at a loss here, any help would be greatly appreciated.

[jmr061]

Have you double checked all the internal coax lines and mad sure they are all connected? The one that goes from the rx front end to the vco is a bit tricky. Just a thought.

Also back the squelch down to zero and make sure you at least get squelch noise.

Jason

[scooter783]

I have backed the squelch down to 0 (at 2 I will even get noise). Haven't yet checked the internal coax lines though.... Thanks.

[Will]

Scooter,

Just changing the leaking capacitors will not correct the problem you have.
What you (seem to) have is permanent damage to the circuit board and components.

[scooter783]

Will,

Thank you for the post; however, that was not news I wanted to hear. Assuming that there is permanent damage, what would you recommend that I do (short of getting a different radio)?

[kc7gr]

Will,

Thank you for the post; however, that was not news I wanted to hear. Assuming that there is permanent damage, what would you recommend that I do (short of getting a different radio)?

Unfortunately, once that capacitor gunk eats into the inner layers, the target board is history. There's simply no easy or reliable way to reconnect corroded PC traces that never appear on the board's outer layers (those boards, if I recall correctly, are at least four-layer).

You have two choices: Find a replacement radio, or find a 'donor' radio and swap boards from it. The RF board is the only one that's band-sensitive, though it is my understanding that they can be configured for any of the Spectra bands with minimal effort. In either case, make and save a copy of your codeplug before you do anything else.

Be prepared to replace the caps on either the replacement radio or the donor boards as a preventive measure. One step that people do miss with this is the critical one of CLEANING THE BOARDS once the bad caps are removed. I've had good luck using 99% isopropanol (better known as denatured alcohol). Will may know other tricks.

Do not, under any conditions, use anything less than 99%, and most especially not rubbing alcohol. Such will leave water residue behind. You can find the right type of alcohol at either Fry's or most large electronics distributors.

If you replace the boards as a pair (command and RF, both from the same source), you should not need to do any kind of alignment. You will have to reinitialize the command board to your original memory module if you end up keeping it. Alternatively, if the donor radio is the same band, you could just keep its memory module and dump your codeplug into it.

If you replace, say, just the RF board, be prepared to do a full alignment of the radio (the board-replacement process in the RSS absolutely requires it) using a service monitor or appropriate discreet test gear.

If you decide that this is too overwhelming, or you do not have access to the necessary test gear, either myself or Will can handle the repair. A PM to whoever you choose will work, and the choice sometimes comes down to geography and workload (I'm southeast of Seattle, Will is in southern California).

Happy tweaking.

[jackhackett]

I've had good luck using 99% isopropanol (better known as denatured alcohol).

Not the same thing, two different alcohols (C3H8O vs. C2H6O), denatured is simply ethanol with some additive to make it undrinkable. Take it from Father Jack, I know alcohol

I've used household ammonia to clean the boards, which in theory should help neutralize the acid in the leaked electrolyte, followed by 99% isopropanol.

[ke4zdg]

Jack,

Going back to my anhydrous ammonia experimentation days (built a homemade refrigerator) and my blueprint machine days, I remembered ammonia eating the poo out of copper/brass stuff. Wouldn't that ruin the radio soaking copper-foil-trace circuit boards in ammonia? I could see where the basic properties of ammonia would counteract the acidic properties of boric acid (the electrolyte), but ammonia and copper makes an equal mess.

Jared

[jackhackett]

I don't soak the boards in it, I just use some on a small brush to clean the area around the caps, and as I said I follow it with alcohol. Household ammonia is a relatively weak solution, I haven't seen any ill effects of using it yet (of course that may just be the alcohol talking).

[kc7gr]

I've had good luck using 99% isopropanol (better known as denatured alcohol).

Not the same thing, two different alcohols (C3H8O vs. C2H6O), denatured is simply ethanol with some additive to make it undrinkable. Take it from Father Jack, I know alcohol

I've used household ammonia to clean the boards, which in theory should help neutralize the acid in the leaked electrolyte, followed by 99% isopropanol.

Thank you for the clarification. HOWEVER -- I would never use any type of ammonia or ammonia-based cleaner on PC boards, especially not Spectra boards that have already seen capacitor-leakage damage.

The reason is that the leaking electrolyte has -- guess what? -- a high ammonia content. That's what causes the damage to the boards in the first place.

If there is a need to neutralize an acidic compound, I'm still a fan of a simple baking soda/purified water solution.

Happy tweaking.