BC800XLT Schematic

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bonnema

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I'm looking for a schematic for the BX800XLT made by Uniden shortly after they purchased Electra. It would help if there were reference voltages on the schematic.
The problem with my radio is that the display is very dim and I've replaced the capacitors to get the other voltages up to normal, but I suspect that the transformer that drives the display may be bad. Any thoughts?
Thanks
 

wmbio

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Bc800

Maybe others will have a full schematic for you.

In my 40 years working on older Bearcat scanners here are my suggestions.

!. C98, install a 47 uf at 50 V. Goes bad 100% of the time
2. Your nixies may have just burnt out.from old age

Never seen the transformer be bad!

Good luck
Enjoy
Wmbio
 

bonnema

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BC800XLT

I replaced the cap and one other to get the + and - voltages up to what they should be but the XFMR also puts out an AC voltage to the display and I don't know how much voltage that should be. I'd really like a schematic of the display/keyboard sub assy because hopefully that would have some voltages listed.
 

wmbio

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The secondary of the transformer has two windings,

The first provides 7.8 vac to the tripler for making the positive voltages of 23.6v at TP 6.and

Neg voltages 23.6V on one side of R107 and neg 18.0v on the other side of the same resistor..

The other secondary provides pos 12.6 VAC and neg 12.6 vac for the heaters of the nixie tubes
 
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bonnema

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Mar 29, 2014
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BC800XLT

The AC voltage is what I needed to know. Thanks!

In this case, capacitors do make a difference as they are used to couple energy into the xfmr and to the tripler. Mine were both low in capacitance with the resultant low voltage output.

I'd still like to see a schematic of the display/keyboard sub-assembly

Thanks again for the respones.
 
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