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Rficon
Junior Member
Username: Rficon
Post Number: 10
Registered: 2-2005
| | Posted on Friday, February 18, 2005 - 8:07 pm: | 
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I just got my Connex 4800dxle. I was planning on using the mods for the EPT690010z board as stated on http://www.radiomods.co.nz/
But, I opened it up to verify the the board, and I noticed it was a EPT690010c, not a EPT690010z. Are these boards the same?
The mod I wanted to perform is the "Super Swing Modification" which includes adding a 1n4001 diode to R264. Will this mod work on the EPT690010c the same way it works on the EPT690010z?
Any help, or mods for this board would be appreciated.
Thanks,
RFIcon |
Tech808
Moderator
Username: Tech808
Post Number: 4931
Registered: 8-2002
| | Posted on Sunday, February 20, 2005 - 7:08 am: |
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Rficon,
Sorry,
I have not heard of anyone doing this mod to the 93T radios.
Maybe one of the other copper forum members can offer some advice or help.
Lon
Tech808
CEF808
N9OSN |
Rficon
Junior Member
Username: Rficon
Post Number: 14
Registered: 2-2005
| | Posted on Sunday, February 20, 2005 - 4:46 pm: |
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Thanks Tech808.
I appreciate the response. The more I look at the boards, the more I think this mod will work. I am going to study the boards a little more before I try it out.
Is there another swing mod for the EPT690010c board? With the popularity of the 93T and the 4800, I am a little surprised there is not more info on the internet about this board.
Thanks,
RFIcon |
Therealporkchop
Intermediate Member
Username: Therealporkchop
Post Number: 151
Registered: 11-2002
| | Posted on Sunday, February 20, 2005 - 10:21 pm: |
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I had a 93T and a local shop performed this mod to it. It seemed to work ok, but I removed it and the radio seemed to work better for just adjusting the modulation from the pot on the board. I assume the 4800 doesn't have the same amp final as a 93T, so maybe your results will be better. So guys say leave the factory resistor, but I have better luck putting a 100 ohm resistor with the diode. Atleast on my Galaxy 77 I did. Maybe this will help you.
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Rficon
Junior Member
Username: Rficon
Post Number: 15
Registered: 2-2005
| | Posted on Tuesday, February 22, 2005 - 1:12 am: |
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Therealporkchop,
Do you remove R264 all together and replace with a 100ohm resistor and a 1n4001, or do you keep R264 then attach a 100ohm resistor then the 1n4001? What is the purpose of the 100ohm resistor?
I started with a stock radio, modulation limiter in place and modulation vr cranked open. I did this mod(just adding the 1n4001) to my Connex 4800dxle(EPT690010c). It seems to be working correctly. 1.5 watt dead key swings to 35. No problems barefoot.
The whole reason for doing this mod was to modulate my amp at a 1:4 carrier to peak ratio. I can now achieve this as 110 swinging to 450, with side effects.
Here is where I encountered a problem. With the amp on(only with amp on) the frequency counter goes wild when I modulate into the mic(D104 set on 5) bouncing all over, dead key is fine. At his point I was sure that it was over modulating. After adjusting the modulation VR in the radio(it was very touchy after the 1n4001)and on the mic, I was able to stop the wild frequency fluctuations while modulating. The next problem is at this setting, I loose 50 watts of swing. Down from 450, kind of defeating the purpose.
I suspect that over modulation is my problem, and due to the 1n4001 mod it has become very difficult to adjust for full modulation without (excuse the pun) freaking out the counter. I will try to get access to a scope to check it out before I make my final analysis.
Any information would be greatly appreciated.
Thanks,
RFIcon |
Therealporkchop
Intermediate Member
Username: Therealporkchop
Post Number: 185
Registered: 11-2002
| | Posted on Sunday, April 24, 2005 - 1:41 am: |
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Well, let's see. I read somewhere that most guys doing the diode mod were doing it wrong. I've seen where guys have used a 51ohm resistor and a 1n914 together hooked onto the solder side of the board on the 2sb754 transistor. This works fine if you want to set your deadkey down low and keep it there, but that ain't my style. Removing r264 completely and then installing the 100 ohm with the 4001 works better for me. My experience has been that using the before mentioned mod on the solder side caused modulation to drop off below 100% if I turned up my deadkey to just 4 watts. I don't always want to use an amp, and most of the time I don't. But I want that swing and I want that extra kick.
Using the 100 ohm resistor was what some guy wrote somewhere, I don't remember where I read it. Of course a lot of guys will say "you just do everything you read", well, yes I try most of what I read. And of course, what works for guy A might not work for guy B. Maybe there is no difference, atleast I don't really see any on my scope. Doing either of these mods with any resistor/diode combo just causes over modulation and audio drop out for a finite amount of time. If you've used a scope, you've seen this. BUT, most radios I've done it do seem to respond well and nobody complains about the audio???? Go figure... |
Therealporkchop
Intermediate Member
Username: Therealporkchop
Post Number: 186
Registered: 11-2002
| | Posted on Sunday, April 24, 2005 - 1:44 am: |
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"I suspect that over modulation is my problem, and due to the 1n4001 mod it has become very difficult to adjust for full modulation without (excuse the pun) freaking out the counter."
I would say you are getting over modulation. Turning down the deadkey will get you the modulation you want, and if your experience goes like mine, then turn up the deadkey and it will kill down some of the modulation with this mod. I'd think that the counter problem was either over modulation (maybe) or most likely harmonics, did you stretch any of the choke coils? |
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