BC100/BC200: Trying to bring a BC200XLT back to life

[gearhead1961]

I dug out my ancient BC200XLT the other day and decided to bring it back from the dead. I have a difficult problem (well, its difficult for me anyway). The battery was a goner so I purchased a replacement pack from Batteries America, soldered it in and charged it for 24 hours using the OEM charger. Now, the scanner will operate fine while plugged into the wall wart but its still dead when I try to run it on the battery.

Here's where it gets weird: I have 7+ volts at the battery terminals. If my newly refurbished battery is putting out the correct voltage, why won't the scanner operate when the current to the radio flows through those same terminals when connected to the AC adapter?

Any suggestions would be appreciated!

Neal
KK7PCE

 

[RandyKuff]

I had that scanner many moons ago...
The slide on battery pack uses Nickle Cadmium (NiCd) batterys...
Is that what type of batt's you purchased to rebuild the pack?

If you used Nickle Metal Hydride (NiMh) batts they won't charge correctly...
NiMh's are higher voltage (And current) than NiCd battery's
Also measuring the pack voltage without loading it won't tell you to much...

 

[wtp]

yes to what RandyKuff said.
you can use a new charger on the old nicads, but you should not use stuff meant for nicads on NiMh.
and i had a cell years ago that tested on a good high resistance tester that could not light a bulb.
it sound weird, buy digital (very high) and good 50K ohms/v resistance testers are not good testers for cells.
a nice cheap 5k ohms is good or....a two cell bulb or 3V, like from a two cell flashlight.
that is what he meant by loading it, putting a load like a bulb on it.
and there might be a problem in between where the battery hooks in and the charging part.

 

[gearhead1961]

The replacement pack is a NiCd battery. I will place a load on it and report back. Thanks!

 

[mc48]

You can replace NiCad's with NiMH, they are both 1.2v. I used them in my 200XLT packs for years, I would verify the polarity of the new cells.

 

[RandyKuff]

You can replace NiCad's with NiMH, they are both 1.2v. I used them in my 200XLT packs for years, I would verify the polarity of the new cells.

Sure you can use NiMh batt's in place of NiCd batt's...
That scanner uses a proprietary battery pack... Your not using idividual cells with an external charger...
The scanners charging circuit is not the correct algorithm for NiMh batt's, it uses CCCV (Constant Current Constant Voltage)...

• Nickel- and lithium-based batteries require different charge algorithms. A NiMh charger can charge NiCd; a NiCd charger would overcharge NiMh batt's and destroy them over time.

 

[n1chu]

Sure you can use NiMh batt's in place of NiCd batt's...
That scanner uses a proprietary battery pack... Your not using idividual cells with an external charger...
The scanners charging circuit is not the correct algorithm for NiMh batt's, it uses CCCV (Constant Current Constant Voltage)...

• Nickel- and lithium-based batteries require different charge algorithms. A NiMh charger can charge NiCd; a NiCd charger would overcharge NiMh batt's and destroy them over time.

It’s a BC200XLT, not a SDS200…

 

[RandyKuff]

It’s a BC200XLT, not a SDS200…

I know what it is...
I had one years ago...

 

[gearhead1961]

The new batteries are NiCads and the polarity is correct.

 

[RandyKuff]

The new batteries are NiCads and the polarity is correct.

Did you try putting a load on the the pack yet?

 

[KevinC]

I could be completely wrong, but IIRC the battery power runs through the external power jack, so your jack may be bad or oxidized. Thereby not allowing the battery to power the radio.

I seem to remember people having the same issue, radio would operate on external power and the battery would charge, but it wouldn’t run on battery power due to a bad jack.

 

[RandyKuff]

I could be completely wrong, but IIRC the battery power runs through the external power jack, so your jack may be bad or oxidized. Thereby not allowing the battery to power the radio.

I seem to remember people having the same issue, radio would operate on external power and the battery would charge, but it wouldn’t run on battery power due to a bad jack.

That could be...
It's been years since I had that scanner... I don't recall if that was how the power jack was set up either...
Although I did rebuild the battery pack for it once...

 

[n1chu]

I know what it is...
I had one years ago...

I wasn’t aware the BC200XLT had a battery pack instead of being powered by common AA Nicads or NMHs. So I thought there might be a confusion over the model numbers.

 

[Ubbe]

The battery was a goner so I purchased a replacement pack from Batteries America, soldered it in and charged it for 24 hours using the OEM charger. Now, the scanner will operate fine while plugged into the wall wart but its still dead when I try to run it on the battery.

The old battery where probably fine but the scanner already had that issue that it couldn't be powered from the battery, so you assumed it was a battery issue and not the actual scanner that needed to be repaired. I will check if it's possible to get a schematic for a BC200XLT. Old Unidens scanners seem to have some schematics available. It could be like KevinC mentions, a bad switch in the charge connector.

Edit: Schematics found. No connector issue possible. It's a charger IC 601 that most certainly are the problem, or at least its connections to the battery pack.
Edit2: But yes, it can be that connector when looking in the schematics, as the batteries negative connector goes thru the connector and then to ground. It's a 27 ohm resistor in series to ground to limit the charge current when a charger are plugged in. To test, remove the charger plug and ground the negative terminal of the battery, perhaps antenna ground are a good place to use. If you can't get to the battery terminals then ground all pins on the charge connector and one of them are the one that goes to battery minus..





/Ubbe

 

[RandyKuff]

I wasn’t aware the BC200XLT had a battery pack instead of being powered by common AA Nicads or NMHs. So I thought there might be a confusion over the model numbers.

 

[RandyKuff]

The old battery where probably fine but the scanner already had that issue that it couldn't be powered from the battery, so you assumed it was a battery issue and not the actual scanner that needed to be repaired. I will check if it's possible to get a schematic for a BC200XLT. Old Unidens scanners seem to have some schematics available. It could be like KevinC mentions, a bad switch in the charge connector.

Edit: Schematics found. No connector issue possible. It's a charger IC 601 that most certainly are the problem, or at least its connections to the battery pack.
Edit2: But yes, it can be that connector when looking in the schematics, as the batteries negative connector goes thru the connector and then to ground. It's a 27 ohm resistor in series to ground to limit the charge current when a charger are plugged in. To test, remove the charger plug and ground the negative terminal of the battery, perhaps antenna ground are a good place to use. If you can't get to the battery terminals then ground all pins on the charge connector and one of them are the one that goes to battery minus..

View attachment 166826

View attachment 166828

/Ubbe

It's fine with the AC adapter barrel connector,,,
But maybe not spinging back enough to connect the battery when the AC adapter is removed...
Could easily prove that by plugging in a shorted barrel connector...

 

[Ubbe]

Could easily prove that by plugging in a shorted barrel connector...

Look at the schematics for the switch. It doesn't help to use a shorted plug as the switch part that goes to the battery minus have no connection to the actual plug, that mechanically lifts the springed part, by an isolated plastic piece, that goes to the battery. It has to be done from the inside of the scanner as trying to insert a copper wire or similar connected to ground and then trying to touch that part from the outside will be difficult if not impossible.

As a quick test, a spray of a good amount of contact cleaner and then exercise the connector by plugging and unplugging many times might work if not wanting to take the backside off the scanner.

/Ubbe

 

[Ronaldski]

I had a 200xlt as well. I recall at times the contacts on the battery would get dirty for some reason and the spring loaded contacts where it connect on the radio. I used isopropyl alcohol on a cotton swab to clean all the contacts.

 

[gearhead1961]

We have a winner!

I used DeOxit on the charge connector of the battery pack and plugged / unplugged the connector a few dozen times. Radio now operates on both AC and battery.

Thank you to all!

 

[KevinC]

We have a winner!

I used DeOxit on the charge connector of the battery pack and plugged / unplugged the connector a few dozen times. Radio now operates on both AC and battery.

Thank you to all!

You're very welcome!