RCI X9HP EPT950M10C need bias settings and unlock clarifier

[357]

My buddy bought one of these. (it was too late to stop him)
It sucks ass on SSB was no audio and crunchy real bad. I bumped up the bias by ear and it really helped alot but it'd be nice to know what it should be.
I also nudged the tx freq but it needs to be unlocked because they all drift like like sh%t.

Anyone got any mods for these?

thanks

heres a before and after

https://files.catbox.moe/fexnjo.wav

https://files.catbox.moe/xa31kt.wav

 

[Shadetree Mechanic]

View attachment 69185


My buddy bought one of these. (it was too late to stop him)
It sucks ass on SSB was no audio and crunchy real bad. I bumped up the bias by ear and it really helped alot but it'd be nice to know what it should be.
I also nudged the tx freq but it needs to be unlocked because they all drift like like sh%t.

Anyone got any mods for these?

thanks

heres a before and after

https://files.catbox.moe/fexnjo.wav

https://files.catbox.moe/xa31kt.wav

I bought one a while back from Superior CB and unfortunately it has raspy TX in SSB. Not really bad, but enough to make it a shelf queen. I think the clarifier is unlocked, I will pop the cover and take a look.

As far as the bias, I have a power supply with a ammeter in it. I checked the amp section by slowly turning the bias up while keyed in sideband with no audio. Watch the meter to see when the transistors turn fully on, then back it dow a hair and key a few times to make sure it doesn't get "stuck" on. My next step is to check the bias of the radio itself, when I get more bench time.

 

[357]

hey thanks.
ya the audio is weak at full blast, the stock mike sucked so I wired up a old GE hand mic that woke it up a bit. the bias really was like night and day. also the am mod pot wil shit itself after 50-60% so dont turn that up.
this thing does pull some power my old ps30 was flickering the lights in here with 260pep on am. I put it about 190 on ssb

 

[Shadetree Mechanic]

I run a Zetagi base mic with mine. Unfortunately Zetagi went out of business though. Mine is not the HP, so it only does 150w. I wonder what the difference is, maybe different transistors? I think I found the clarifier mod, looks pretty simple.

Cut the orange wire off the clarifier plug and put it to 8v.

 

[Dr. Frankenstein]

Do what you want but.....................

That's only half the work ..... Like any other clarifier circuit being unlocked the "VR8 TX F C" circuit has to be disabled to actually work properly. Either take out VR8, cut a trace to VR8, or take out a diode in the VR8 circuit.

I know this because all locked clarifiers are controlled by the Transmit potentiometer (in this case VR8 TX) being set to Frequency Center (F.C.).

If you're still having problems with the Orange wire jumped to 8 volts ..........
Just lift the Orange wire from 8 volts and see if the radio is still locked on frequency when transmitting.

I may be wrong, but what do I know ...... I've only unlocked too many clarifiers to count.

I don't often post anymore, but this is just my 2¢ worth........................

 

[Shadetree Mechanic]

Do what you want but.....................

That's only half the work ..... Like any other clarifier circuit being unlocked the "VR8 TX F C" circuit has to be disabled to actually work properly. Either take out VR8, cut a trace to VR8, or take out a diode in the VR8 circuit.

I know this because all locked clarifiers are controlled by the Transmit potentiometer (in this case VR8 TX) being set to Frequency Center (F.C.).

If you're still having problems with the Orange wire jumped to 8 volts ..........
Just lift the Orange wire from 8 volts and see if the radio is still locked on frequency when transmitting.

I may be wrong, but what do I know ...... I've only unlocked too many clarifiers to count.

I don't often post anymore, but this is just my 2¢ worth........................

I am not sure what has been done to make the mod work besides moving the orange wire to constant 8 volts. Do you know of a schematic for this radio? I am not really sure what is what.

 

[357]

I run a Zetagi base mic with mine. Unfortunately Zetagi went out of business though. Mine is not the HP, so it only does 150w. I wonder what the difference is, maybe different transistors? I think I found the clarifier mod, looks pretty simple.

Cut the orange wire off the clarifier plug and put it to 8v.

View attachment 69196View attachment 69197View attachment 69198

thanks for that. I'd imagine they would have to remove something like a diode or 2 or some jumpers?

 

[Shadetree Mechanic]

thanks for that. I'd imagine they would have to remove something like a diode or 2 or some jumpers?

Let me see if I can logic through this.
Stock operation switches power when keyed between the pot on the front of the radio to the pot inside. While in rx, power is applied to the front pot, not the inside pot. Moving the orange wire on the front pot to constant 8v would be the same in rx. But tx would cause the pot inside to be energized too. So the inside pot needs to be disabled.

Sound correct?

 

[Shadetree Mechanic]

I don't see anything that stands out, if you compare it to yours maybe you can spot something.

 

[Shadetree Mechanic]

Ok I think I see something missing to the bottom left of vr8.


.

 

[357]

Ok I think I see something missing to the bottom left of vr8.


.View attachment 69201

yes looks like 2 diodes

 

[357]

So I (I'll admit it) cross threaded the coax connector or something when my buddy left and talked to him on the way home yesterday but I guess it wasnt on tight and this moring he was trying to call skip then he said the needle stopped moving. I told him to check the fuses and he said the antenna connector fell off he barely touched it.
So it fried a rt1, the one closest to the antenna jack.
I replaced all 3 with 13N10's but it still sounds crunchy unless I turn the bias way up.

what a cluster fu%k

but the clarifier mod looks good thank you

 

[Shadetree Mechanic]

I would think that if there was an antenna problem, the amp section would take the hit. Might have been too much bias on the RT1s?

 

[357]

ok I got the clarifier unlocked but its not on center slot.
If I adjust the cans, that changes the IF shift so it sounds real bassy on lsb and real tinny on USB.
I wonder how to center it with out messing up the carrier shift?
maybe there is a third item to remove?

 

[357]

I would think that if there was an antenna problem, the amp section would take the hit. Might have been too much bias on the RT1s?

I thought that too. I'm not sure but the antenna connector not on all the way didnt help