Search found 684 matches

by Goldfinger
Fri Aug 06, 2021 8:44 am
Forum: rx and tx mods
Topic: President Lincoln 2
Replies: 1
Views: 1140

Re: President Lincoln 2

On the schematic on the output side (left end) of R108, it shows "R99" going to ground. It also says NC with R99 meaning "no connection" (not installed). If you install a resistor from the left end of R108 to ground, it will allow the limiter pot to go higher in modulation. Try a...
by Goldfinger
Mon Aug 02, 2021 11:43 am
Forum: rx and tx mods
Topic: rci n4
Replies: 6
Views: 709

Re: rci n4

C262 is closer to the front right side, behind the 4558 mic amp IC. You want to inject through a 10uF to the left end of the cap.
DX2995 C262 amod.jpg
DX2995 C262 amod.jpg (413.31 KiB) Viewed 679 times

To get response below 80Hz, you need to change C260 to a 330uF, 25V electrolytic. Observe polarity.
DX2995 C260mod.jpg
DX2995 C260mod.jpg (322.57 KiB) Viewed 677 times
by Goldfinger
Wed Jul 28, 2021 2:28 pm
Forum: rx and tx mods
Topic: rci n4
Replies: 6
Views: 709

Re: rci n4

Looks like the ept695015br is very close to the ept695015a in the 2995 so the other thread you found looks like it has the information you need.
by Goldfinger
Wed Jul 28, 2021 9:07 am
Forum: rx and tx mods
Topic: rci n4
Replies: 6
Views: 709

Re: rci n4

On first look, I'm not seeing a schematic anywhere. Do you know where there is one or which EPT board the PC board is?
by Goldfinger
Tue Jul 20, 2021 8:07 am
Forum: Microphones & Mic Wiring
Topic: Cobra CA60 Desk MIcropone to HiFi
Replies: 5
Views: 1245

Re: Cobra CA60 Desk MIcropone to HiFi

Yeah, I didn't mention the caps to ground because they were already pretty small, value-wise. Lowering them wouldn't have achieved much.
by Goldfinger
Sun Jul 18, 2021 10:23 am
Forum: Microphones & Mic Wiring
Topic: Cobra CA60 Desk MIcropone to HiFi
Replies: 5
Views: 1245

Re: Cobra CA60 Desk MIcropone to HiFi

On the high end you can change the positive feedback cap on Q1 to get some more boost at higher frequencies.
Change C5 to a .002 or .0047uF. The higher the value the more rise there is to the high frequencies.
by Goldfinger
Sat Jul 17, 2021 8:22 am
Forum: Microphones & Mic Wiring
Topic: Cobra CA60 Desk MIcropone to HiFi
Replies: 5
Views: 1245

Re: Cobra CA60 Desk MIcropone to HiFi

With all of those 4.7uF caps, it already looks pretty wide. About all you could do to maybe get a little lower would be to change C2 and C3 to 10uF, 16V.
If you've tried it on a wide radio as is and it didn't sound very wide, it may be the mic element itself.
by Goldfinger
Thu Jul 08, 2021 3:48 pm
Forum: rx and tx mods
Topic: RCI-6900
Replies: 0
Views: 1093

RCI-6900

Receive: Change C87, C48. C193 to 4.7uF (475) SM, polyester or Non-polarized electrolytic Transmit: Change C163 to a 10uF (106) observe polarity Change C164 to a 2.2uF (225) observe polarity Change C199, C262 to 4.7uF (475) Change C260 to a 330uF, 16 volt electrolytic, observe polarity Direct injec...
by Goldfinger
Thu Jun 24, 2021 3:14 pm
Forum: rx and tx mods
Topic: President Richard
Replies: 4
Views: 624

Re: President Richard

TX: Change C305, C315, C316, C318, C319, C321 C327 to 1uF (105P) Change E300 to a 330uF, 25 volt. Observe polarity Direct inject through a 4.7uF to the R366, R367 end of C318 A little more gain for a noise cancelling stock mic? Change R305 to a 100K No guarantee's on how well this will work. The in...
by Goldfinger
Wed Jun 16, 2021 10:24 am
Forum: rx and tx mods
Topic: President Richard
Replies: 4
Views: 624

Re: President Richard

I have a lot going on for the next couple days but I'll stare at it when I can and post up some info soon.
by Goldfinger
Thu May 20, 2021 3:52 pm
Forum: rx and tx mods
Topic: Tram D201 hi fi
Replies: 7
Views: 2920

Re: Tram D201 hi fi

yes
by Goldfinger
Tue May 04, 2021 3:57 pm
Forum: rx and tx mods
Topic: Tram D201 hi fi
Replies: 7
Views: 2920

Re: Tram D201 hi fi

Connecting at B38 is effectively the same as pin 9 so you could connect there. If a guy wanted to disconnect the output of V601a to minimize any "noise" from possibly being introduced from previous stages, I would remove C612. Of course this disables the ability of using the mic jack for A...
by Goldfinger
Mon Apr 26, 2021 8:44 am
Forum: rx and tx mods
Topic: Galaxy 77/88/99/Melaka etc.
Replies: 10
Views: 7260

Re: Galaxy 77/88/99/Melaka etc.

After bypassing echo board alone, tx audio is super bass-y without tx cap changes. Any change to bring up the TX highs to match the lows? Thanks. There isn't much shunt capacitance that can be lowered any more to easily get more highs. You could try making C128 lower in value. Try changing it from ...
by Goldfinger
Thu Apr 08, 2021 2:09 pm
Forum: Microphones & Mic Wiring
Topic: Astatic 878DM bass boost?
Replies: 3
Views: 1077

Re: Astatic 878DM bass boost?

Nice! :mrgreen:
by Goldfinger
Wed Apr 07, 2021 7:41 am
Forum: Microphones & Mic Wiring
Topic: Astatic 878DM bass boost?
Replies: 3
Views: 1077

Re: Astatic 878DM bass boost?

Change C3, C4 to .22uF or .47uF disc or mylar.
by Goldfinger
Sat Mar 27, 2021 9:21 am
Forum: rx and tx mods
Topic: Request - Stryker 955 cap mods
Replies: 26
Views: 7452

Re: Request - Stryker 955 cap mods

I wasn't sure if the bypass cap would work as I only had the schematic and not an actual radio to try it. There may be some DC voltage there the cap doesn't like. You may have the cut the wires on pin 4 of J902/CON4 and pin 3 of J903/CON3 and connect the wires together. (the wires from the radio sid...
by Goldfinger
Mon Mar 15, 2021 4:51 pm
Forum: rx and tx mods
Topic: hifi rx/tx mods for Stryker 497hpc?
Replies: 5
Views: 1383

Re: hifi rx/tx mods for Stryker 497hpc?

Receive: Change C36, C39, C155, C154 to 2.2uF or 4.7uF - 25V or higher NonPolar electrolytic or mylar Change C157 to 2.2uF or 4.7uF - 16 volt or better Tantalum or electrolytic, observe polarity Change C145 to a 1000uF - 25 volt or higher electrolytic Transmit: You have to bypass the echo before you...
by Goldfinger
Fri Mar 12, 2021 11:30 am
Forum: rx and tx mods
Topic: hifi rx/tx mods for Stryker 497hpc?
Replies: 5
Views: 1383

Re: hifi rx/tx mods for Stryker 497hpc?

I'm real busy today but I'll post it up soon.
by Goldfinger
Sat Mar 06, 2021 8:50 am
Forum: >>> HIGH FIDELITY AUDIO Q and A <<< POST QUESTIONS AND COMMENTS HERE!
Topic: Washington Base, 858, No Mod
Replies: 2
Views: 561

Re: Washington Base, 858, No Mod

The best way to track down an audio problem is to inject a 1K tone into the mic jack then trace the signal through the mic amp circuit with an oscilloscope and see where it drops out.
by Goldfinger
Fri Mar 05, 2021 9:02 am
Forum: rx and tx mods
Topic: Connex 3300 AM Regulator issue.
Replies: 2
Views: 544

Re: Connex 3300 AM Regulator issue.

I've hifi'd so many radios I know it's not the cap change itself that is causing your problem. One thing I have found over the years on the regulator is a burr on the chassis mounting hole that slightly lifts the transistor so it's not seated flush against the metal. You have to remove the regulator...
by Goldfinger
Fri Feb 19, 2021 3:00 pm
Forum: Microphones & Mic Wiring
Topic: Handheld D104 Cap Changes
Replies: 1
Views: 522

Re: Handheld D104 Cap Changes

They already have enough highs but you can accentuate the lows by changing the 270K on the left to 470K, 680K or 1Meg. The higher the value the larger the bass boost. The caps are already 4.7uF so are already large enough for good bass transmission.
D104M6Bschematic.jpg
D104M6Bschematic.jpg (25.51 KiB) Viewed 520 times
by Goldfinger
Fri Feb 19, 2021 1:07 pm
Forum: rx and tx mods
Topic: Anytone AT-6666 (Quad 6) hifi
Replies: 18
Views: 3248

Anytone AT-6666 (Quad 6) hifi

The Anytone AT-6666 is the same as the Lincoln II Plus. TX:: Mic amp: Change C571, C570, C530, C527 to 2.2uF non-polar/bi-polar AM regulator/modulator: Change C153, C152 to 2.2uF non-polar/bi-polar. Change E14 to a 330uF 25 volt electrolytic, observe polarity Direct Inject through a 4.7uF, 25 volt e...
by Goldfinger
Thu Feb 18, 2021 9:05 am
Forum: rx and tx mods
Topic: Galaxy Saturn(non turbo) Tx & Rx Cap Request
Replies: 1
Views: 502

Re: Galaxy Saturn(non turbo) Tx & Rx Cap Request

Should be the same as the "Galaxy 77/88/99/Melaka etc" thread pinned at the top of the "rx and tx mods" section
by Goldfinger
Wed Jan 06, 2021 10:19 am
Forum: rx and tx mods
Topic: Request - Stryker 955 cap mods
Replies: 26
Views: 7452

Re: Request - Stryker 955 cap mods

The echo schematic looks like it's missing some circuitry (which happens with Galaxy/Ranger/Stryker schematics) but it looks like you could bridge a 10uF - 16 volt cap from:

- of cap to pin 4 of J902/CON4
+ of cap to pin 3 of J903/CON3
by Goldfinger
Mon Dec 28, 2020 10:07 pm
Forum: rx and tx mods
Topic: 858 sideband chassis hifi
Replies: 4
Views: 2306

Re: 858 sideband chassis hifi

Yes, looks like a typo...
Thanks for pointing it out. I'll revise C95 to 1000uF.

Edit: until I update the forum software, I can't edit the older post, This post will have to reflect the revision.
by Goldfinger
Sat Dec 05, 2020 6:58 pm
Forum: rx and tx mods
Topic: 2980WX?
Replies: 2
Views: 568

Re: 2980WX?

Looks like it's the same as a DX959.

That mod can be found Here
by Goldfinger
Thu Dec 03, 2020 10:23 am
Forum: rx and tx mods
Topic: Galaxy 86v request
Replies: 4
Views: 1616

Re: Galaxy 86v request

If that is true, the 86V may have the same layout as a DX2517 or a DX2547. The hifi mods may be the same as these radios.
Thanks rangerrci. :mrgreen:
by Goldfinger
Thu Dec 03, 2020 10:18 am
Forum: rx and tx mods
Topic: Connex saturn 33 ssb 360015c board cap change
Replies: 1
Views: 499

Re: Connex saturn 33 ssb 360015c board cap change

That board is already on the forum. I see it was a little tricky to find using the search function.
You can find it Here
by Goldfinger
Tue Nov 10, 2020 8:39 am
Forum: rx and tx mods
Topic: 2950, 2970, 2527, DX22b etc. (ept295013z) mods
Replies: 24
Views: 8350

Re: 2950, 2970, 2527, DX22b etc. (ept295013z) mods

C299 for AM, C131 for SSB
by Goldfinger
Thu Oct 22, 2020 7:14 pm
Forum: rx and tx mods
Topic: Request. President Lincoln II plus
Replies: 10
Views: 1361

Re: Request. President Lincoln II plus

Yes, typo. It's supposed to be C153, C152. I edited the original post. Sorry about that... :o :?

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