Pro-32a no longer works on battery

[Sailormannn]

My old Radio Shack Pro-32a no longer works on battery alone. Any ideas on what could be the problem. Have done the usual: replaced batteries, checked voltage at the battery pack, cleaned and checked battery contacts. It works fine when the adapter is plugged into AC power but dead on just batteries. Tried both new rechargeable and new alkaline batteries so know these have power.

Ideas much appreciated.

 

[62Truck]

maybe a cold/broken solder joint on the board

 

[wtp]

if i remember i had a problem with the little tab in the jack for recharging.
i had to push it around a bit, or something like that.

 

[Sailormannn]

if i remember i had a problem with the little tab in the jack for recharging.
i had to push it around a bit, or something like that.

Thanks. I’ll take a closer look. The scanner does work when the adapter is plugged into either the charge or power socket, so power from the adapter works. Wonder if spraying some contact cleaner in the charge socket would help if its something potentially involving the jack.

 

[CycleSycho]

Thanks. I’ll take a closer look. The scanner does work when the adapter is plugged into either the charge or power socket, so power from the adapter works. Wonder if spraying some contact cleaner in the charge socket would help if its something potentially involving the jack.

Sounds like your problem for sure. Those jacks have a metal tab (some with a small contact 'circle' but not all), if the contact area has either debris or carbon buildup, it'll not conduct for the batteries (that are disconnected by the A/C wart when plugged into the radio). Try cleaning the jack, carefully... If you open it up to clean the jack, closely inspect the solder points before spraying into the jack. Good luck!


.

 

[slicerwizard]

Magic 8 Ball says it's the power jack.

 

[Sailormannn]

Magic 8 Ball says it's the power jack.

I squirted some contact cleaner into the power and recharge sockets and looked inside at the power jack assembly and wiring. There are no broken wires so if there’s a problem with the power jack it must be something inside. Haven't squirted any more contact cleaner as it looks like the power jack assembly is pretty well sealed. Still not working when on battery, but works on power.

Any suggestions.

 

[ecps92]

if it runs on the power but not the battery, the issue is likely NOT the power jack, but something between the circuit board and the battery or battery jack. IS this one of the radios that the pack is custom built ? or one with the Yellow or Black insert ?

I squirted some contact cleaner into the power and recharge sockets and looked inside at the power jack assembly and wiring. There are no broken wires so if there’s a problem with the power jack it must be something inside. Haven't squirted any more contact cleaner as it looks like the power jack assembly is pretty well sealed. Still not working when on battery, but works on power.

Any suggestions.

 

[Sailormannn]

if it runs on the power but not the battery, the issue is likely NOT the power jack, but something between the circuit board and the battery or battery jack. IS this one of the radios that the pack is custom built ? or one with the Yellow or Black insert ?

It uses 6 AA batteries inserted in removable tray. The tray is fine as I’m getting power at the contacts. I’ve checked the contacts in the radio and adjusted them; it looks like it’s making contact.

 

[pro92b]

The relevant portion of the PRO-32 schematic is attached. The battery is connected to the power jacks through inductors L110 and L111. If either is an open circuit, the connection from the battery is broken. It is not likely that the inductors are open circuit. R195 is a 39 Ohm resistor used to control charging current. When powering the radio from the battery, the switch in the J7 PWR/CHG jack must be closed, shorting the 39 Ohm resistor. Plugging the AC adapter into the PWR/CHG jack puts the 39 Ohm resistor back into the circuit by opening the switch on the jack. The J6 PWR jack also has a switch inside that can interrupt the connection to the battery. To allow the battery to power the radio both power jacks must be unplugged and both internal jack switches must be closed.

If you remove the battery pack and unplug the ac adapter from the wall socket the battery circuit can be checked with a meter that measures resistance. Measure across the pins of each power jack and see if both switches are on. To easily check J7 just measure across R195 and see if is zero Ohms. Find similar convenient points to measure J6.


If one or both jacks has a faulty switch, spray contact cleaner (Deoxit preferably) into the jacks. Place the radio on its side with jacks facing up to let the cleaner work into the contacts. The plug an unpowered AC adapter into each jack about a dozen times to exercise the switch in the jack. Do the resistance measurements again to see if the switches make contact now. If not rinse and repeat with the contact cleaner.

 

[Sailormannn]

Got it working. I tried plugging in the AC adapter a dozen or so times as suggested to exercise the switch and it’s working now.

Thanks all for your help.

 

[slicerwizard]

Magic 8 Ball never lies...

 

[wtp]

i had not come across the "no connection, try again" with the eight ball...and yet here is proof !