Uniden PC-76 Hi-Fi mods

[350GA]

Good afternoon everyone.

Does anyone happen to have the capacitor locations and values to widen up the TX & RX audio on the PC-76? I have been searching all over with no luck. Thanks in advance!

 

[350GA]

Anyone? Goldfinger possibly?

 

[711]

the problem is the lack of schematics to call out part numbers to change. So you'll have to do a side by side comparison against a 29 for the part numbers. Match the 29 location to your 76 and swap.

From GF forum:
Cobra 29LX with the TDA2003 audio chip

Receive:
Change C33 and C40 to 2.2uF non-polarized electrolytic or mylar
Change C48to a 1000uF, 25 volt Electrolytic, observe polarity

Transmit:
Change C69 to a .001uF disc
Change C68 to a 1.5uF Tantalum with the + side towards the right (audio chip) side of the radio.
Change C37 to a .1uF mylar (or parallel a second .033uF mylar with the existing one)


Cobra 29LTD with the TA7222AP audio chip

Receive:
Change C33 and C40 to 2.2uF non-polarized electrolytic or mylar
More highs?: remove C204 (some year ranges don't have this cap)

Transmit:
Change C69 to a .001uF disc
Change C68 to a 1uF Tantalum (some radio's already have a 1uF in them)
Change C37 to a .068uF mylar (or parallel a second .033uF mylar with the existing one)


New 2010/2011 Cobra 29LTD (TDA2003 audio chip)

Receive:
Remove C170
Change C33 and C40 to 2.2uF non-polarized electrolytic or mylar

Transmit:
Change C68 to a 1.5uF tantalum with the + side towards the right (audio chip) side of the radio.
Change C69 and C125 to .001uF disc
Change C37 and C43 to .1uF mylar

 

[9C1Driver]

And in the end what is it really going to do for you? Not much. Let your PC76 be what it was intended to be, a very nice talking cb radio.

 

[711]

And in the end what is it really going to do for you? Not much. Let your PC76 be what it was intended to be, a very nice talking cb radio.

We are in the modifications section of the forum. Sheesh

 

[350GA]

Thank you 711! I realized that after doing some more research that they are in the same locations as a Cobra 29, just labeled different.

And I personally LOVE the cap mods on the RX side. It makes a big difference in the receive audio quality and helps reduce the white noise hiss. Granted I use different cap values than what Goldfinger recommends to get a particular sound I like, but they work great! Thanks!

 

[711]

Thank you 711! I realized that after doing some more research that they are in the same locations as a Cobra 29, just labeled different.

And I personally LOVE the cap mods on the RX side. It makes a big difference in the receive audio quality and helps reduce the white noise hiss. Granted I use different cap values than what Goldfinger recommends to get a particular sound I like, but they work great! Thanks!

Welcome , I like the receive after swapping caps. So easily done and makes listening more enjoyable. Glad it worked for you

 

[Chris Millas]

Thank you 711! I realized that after doing some more research that they are in the same locations as a Cobra 29, just labeled different.

And I personally LOVE the cap mods on the RX side. It makes a big difference in the receive audio quality and helps reduce the white noise hiss. Granted I use different cap values than what Goldfinger recommends to get a particular sound I like, but they work great! Thanks!

Thank you 711! I realized that after doing some more research that they are in the same locations as a Cobra 29, just labeled different.

And I personally LOVE the cap mods on the RX side. It makes a big difference in the receive audio quality and helps reduce the white noise hiss. Granted I use different cap values than what Goldfinger recommends to get a particular sound I like, but they work great! Thanks!

Just out of curiosity, what value caps did you use for the RX mod instead of the recommended 2.2?

 

[MKwrench]

The higher the uf, the more the highs are blocked and bottom end is put in front.
Grab some 1.0s, 2.2s, and 4.7s to experiment with. I got a solid, thumpy sound from the radios I tried the mods on a few years back.

 

[711]

In my experience, no need to go greater than 4.7iF on the low end, going bigger starts to be an issue especially when you start running big power. Sub low end crap that only analyzes can hear start running a crap load of power on stuff no one will hear unless you run some tight eq settings. If you lift the shunting caps , you get more highs. In the end you either control your audio with an eq or use different cap values to shape your mics audio somewhat. My buddy up in Alaska was running a gate with his SDR and you can hear my lowend rumbling in the pile up. I run a modified D104-m6 and a modded Grant XL.