The schematic on CBTricks is blurry and incomplete so it's unusable. Unfortunately my SAMS are buried in as storage facility 20 miles away and aren't handy.
If we can come up with a "Clean" scan of SAMS book 276 then I could post up the info.

Gimme a day or two to stare at the CBTricks schematics and I'll get it posted..

If it's a DX model, VR8. It will only work if the clarifier is stock.

No, the DAK X has the sideband board in it.

As far as a windup, not sure if anyone has come up with one as there is no clarifier. Yes, the echo would have to be bypassed if you want wide audio through the mic jack. If the TX is going to be direct injected you wouldn't need to. Bypassing the echo can be accomplished by unhooking the Mic I/P fr...

I think D-rail designed a little wind-up circuit for the Stryker. (He is a sharp guy) One can be constructed for any radio with a varactor that doesn't/can't have isolated TX/RX clarifier feeds. It would have to be custom tailored for each chassis and is beyond the scope of the average experimenter....

The D-rail $1600 wind-up mod?

If it's gonna work on the 2547 you would use a 470 or 1000uF, 16V with the + going to the center leg of VR7 (on the front edge of the main PC board) and the - to board ground.

Here ya go: viewtopic.php?f=132&t=16091

I've posted the hifi info for that chassis per a previous request but the 858 sideband chassis is not a good choice to hifi. This is because it uses a modulation transformer that can't pass low frequencies. Direct modulated radios like the 148/Grant XL/2000 or Galaxy/Ranger are better choices.

C542 is also on the feedback circuit of the U500A/U500B team. Both sections aren't there for gain, they are set up for roughly unity gain and are strictly for tone shaping. Most of the mic amp voltage gain is in the earlier stages which are wired for flat response, limited only on the low end by the...

For TX looks like you can make the value of C569 lower.
Try removing C501 to change the feedback circuit of the last mic preamp U500B

With the values in the mod above, since none of the high frequency shunt caps are changed the high end is the same as stock which rolls off about 3.5K-4Khz. On the low end with 1uF caps, it starts rolling off at 60Hz and 3db Down at 45Hz. With a 2.2uF it starts rolling off at 45Hz and is 3db down at...

Lemme know if you find a schematic..

Yes, for the hifi conversion, the uF value is whats important not the style of cap. SMT would be better as it will solder in more securely than grafting in a discrete component.

If it's gonna work the RIT will have to be stock. Try installing a 470uF, 16V or higher electrolytic with the + to either the anode of D150 or the center swiper of VR-111 and the - to board ground.
Changing the value of the cap will change the length of the swoop. (if it works)

Unfortunately the TX and RX must be isolated (fixed frequency on TX) to easily install a windup.

It's been a long time since I worked on one. Does the clarifier work on transmit?
Looking at the schematic it looks like it does.

Not sure but that could be a symptom of low voltage. If the 8 volt TX rail was low it seems like it would affect more parts of the radio. You could put a volt meter on the collector of Q36 and see if it is: A: switching from 0 to 8 volts when you key the mic. B: If it is indeed 8 volts like it's sup...

Looking at the schematic it looks like a wind-up isn't possible as the delta tune circuit is completely different from later 29s. What "might" work is putting a 100uf , 16 volt with the + going to the base of TR21 and the - going to board ground. RX: Change C29 and C90 to 1uF polyester or ...

IC4 is the main 8 volt regulator. Q35 is the switching transistor that is controlled by the TX-Out of the main CPU. Q35 controls Q34 the 8 volt RX source and Q36 the 8 volt TX source. CBS1000 TX Switch Schematic.jpg I couldn't find IC4 or Q34 on the CBTricks board view but I did find Q35 and Q36 CBS...

RV50 (RV5 on this pic) on the front board is the only clarifier adjuster. You sure that isn't the transmit adjuster? On the schematic it's fed by the 8V TX source.

Finding one that's the same input and output impedance as the original would be difficult at best. As far as frequency response you could just inject one and try it. If low bass makes the audio choppy, just roll it off higher. I've injected a Tram D-201 and it handled bass down to 30Hz. Never tried ...

Gimme a couple days to stare at the service manual.

You would inject through a .47uF. 250 volt to the grid end of:
C53 on the Mark 3
C220 on the Mark 4a

It can transmit semi-wide, limited on the low end by insufficient audio transformer core area.

I'm sure it can be done but I don't think CBTricks ever had any instructions for the XLR radios and I've never seen any threads on CB forums either.

Not sure which board a 4600 has.

Receive: Change C224, 229, 232 to a 2.2uF 16V or higher Electrolytic, observe polarity TX: Change C277 to a 2.2uF 16V or higher Electrolytic, observe polarity Change C278 to a 1uF, 16V or higher polyester, mylar of non-polarized electrolytic Change C282 to a 2.2uF 16V or higher Electrolytic, observ...

Great, at least we now know the mod is sound and the clarifier area on the CBTricks schematics are not correct. Chalk up another schematic anomaly to the many I've found over the years on Galaxy schematics...
Thanks for the info!

I hifi'd one back in 2009 for a buddy. He didn't use rack gear so I just did the receive and TX through the mic jack. Sounded pretty deep with a 636 mic.