MTX9000 T/A Problem

[Motoman81]

I have MTX-9000 that has 927 or higher repeaters and T/A frequencies in it for Ham but when I go to T/A I am getting a solid Beep. I heard that this is a VCO problem, and that something in the RSS can be changed for the T/A to be enabled. I have enabled the T/A in the RSS but still get this solid beep. Any help is appreciated.


Stephen

[MTS2000des]

most likely your VCO just won't lock. there is a software mod thread that discussed using LAB to bit bang the tuning values to go down, but the bottom line is the stripline tuning is underneath a sealed can on the RF board which requires a proper heat focus head on an SMT rework station to remove. Par for the course for 900 Jedis', some work great on both 927 repeat and TA, some only work on one but not the other and then there are those that won't work at all.

[fineshot1]

I too have this problem. I have two MTX9000 H01WCH4DN7AN radios. One TX's aok on both 902 & 927 but the other only will TX on 902 and not 927. I went into the RSS and altered the offending units VCO TX tuning parameters to be indentical to the problem units VCO data with still no luck. If anyone has had any success with making one of these problem units please post the solution in detail. It would be much appreciated. Thanks.....dan n2aym

PS-There has been some discussion on another thread(cant remember which one) about possibly " bit banging " some of the TX VCO parameters and I am not familiar with that and perhaps someone can explain in detail how to go about doing that. Perhaps we can find a solution via that method if its possible? just a thought......dan n2aym

[BDB]

I pasted the text from the software mod posting to this post.


In the labware, in labtools 1, there will be an entry for fractional-n synthesizer , f5 I believe. What you are looking at is the hex values for some comparator voltages in the vco control software. the upper left item,TX cp bias, is a setting for the crossover point between the repeat and direct VCO's. If you shift the value down in steps of 500, i.e. if the radio has a value of 6B80 (like mine) try moving it down to say 6800, then down to 6400 then down to 6000. you will need to write the codeplug between each value change. if you reach a point at which the radio will now tx on your lowest freq. then you are set. go too low and the reciever will unlock. On the top right side of the page is the setting for the direct mode. Mine locked fine on repeat (25 meg offset here, thankfully) but not on direct. I shifted the top right value down to 6000 even and all is well now.

[MTS2000des]

just a reminder do NOT use LAB/DEPOT to WRITE to an MTS2000 with a controller version higher than 5.42 unless you want a nice paperweight...

[fineshot1]

Thank you for the additional info. No problem on the MTS2000 as I only have two MTX9000's - but thanks for the warning anyway.....dan n2aym

[MTS2000des]

no prob, would hate to see anyone end up with a FAIL 01/93 brick and a 300 dollar depot bill...

[fineshot1]

Well, it looks like I wont be able to find anyone with labware any time soon.
So I will try to attack this another way - a little experiment so to speak. If any of you out in ham radio land have an MTX9000 and its able to TX on both 902 & 927 with no problem can you please share (PM me) your RSS TX VCO tuning parameters. There are too many parameter combonations to go through in order to try and get this working and I suppose as per some of the other threads it may not work at all but I will try anyway if I can get some input from other MTX9000 users. I can be pmed at " drf3 at verizon dot net "
Thanks.....dan n2aym

PS - I use RSS 6.07

[Max-trac]

Well don't you need Lab to change the value?

I have played with about 10 or 15 of these.
Some will do the 927/902 and TA with no tweaking.
Some will do TA with the Lab tweak described above.

But some WON'T!! And some the RX won't go down to the low end of 927.

Program the lowest freq you will be using, then stick em in the fridge for a couple of hours. If they still lock, great, if not, sell it and try another one.

[fineshot1]

Max-trac - I guess I wasnt clear. I know you dont need labware to tweak the RSS TX VCO values and since I cannot readily obtain it to do the Lab tweak described above I was asking others that were successfull with the RSS TX VCO parameters to share them so I may try them in my HT. I have tried tweaking the RSS parameters with not the success I was looking for. I have TX on 927.5 but need it at the top end of 927 which my HT wont seem to give up. My VCO is at the ragged edge on 927.5 and I wanted to try some other successfull VCO TX parameters.....dan n2aym

[fineshot1]

I pasted the text from the software mod posting to this post.


In the labware, in labtools 1, there will be an entry for fractional-n synthesizer , f5 I believe. What you are looking at is the hex values for some comparator voltages in the vco control software. the upper left item,TX cp bias, is a setting for the crossover point between the repeat and direct VCO's. If you shift the value down in steps of 500, i.e. if the radio has a value of 68B0 (like mine) try moving it down to say 6800, then down to 6400 then down to 6000. you will need to write the codeplug between each value change. if you reach a point at which the radio will now tx on your lowest freq. then you are set. go too low and the reciever will unlock. On the top right side of the page is the setting for the direct mode. Mine locked fine on repeat (25 meg offset here, thankfully) but not on direct. I shifted the top right value down to 6000 even and all is well now.

TNX BDB - I can now confirm this procedure works and works well. I finally bumped into someone that would do it for me. Had the direct mode value changed to 6000. Yahoo - now I can use both MTX9000's to talk to each other......dan n2aym

[AEC]

I never did check to see what the actual VCO settings were in my MTX9000, but every programmed channel has T/A and I use 2 zones with a mixture of 927/902 as well as 935 Conv. frequencies.

Of course, my Firmware is 'ancient'...R01.54

Model: H01WCF4DB5AN

*With firmware this old, it should be able to collect social security checks and medicare!*

As long as it WORKS, it is not broke!

[n9upw]

I pasted the text from the software mod posting to this post.


In the labware, in labtools 1, there will be an entry for fractional-n synthesizer , f5 I believe. What you are looking at is the hex values for some comparator voltages in the vco control software. the upper left item,TX cp bias, is a setting for the crossover point between the repeat and direct VCO's. If you shift the value down in steps of 500, i.e. if the radio has a value of 6B80 (like mine) try moving it down to say 6800, then down to 6400 then down to 6000. you will need to write the codeplug between each value change. if you reach a point at which the radio will now tx on your lowest freq. then you are set. go too low and the reciever will unlock. On the top right side of the page is the setting for the direct mode. Mine locked fine on repeat (25 meg offset here, thankfully) but not on direct. I shifted the top right value down to 6000 even and all is well now.

THANKS BDB!!!!! This worked perfect for me! Now I have 927 TX on my MTX9000!

Derek, N9UPW

[BDB]

I only pasted the text from the original posting relating to the S/W mod. The credit goes to the original poster of the mod. Glad to hear that you had luck with it !