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 Trio 9130 and intermittent output 
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Post Trio 9130 and intermittent output
I have a Trio 9130 with off/on RF output when I key the mic - it happens in FM & SSB. I have traced the RF output up to the driver and all is well. I would like to replace the final PA module (Q1) which is a Toshiba M57727. This part is obsolete and i do not trust Chinese clones. I do, however have some info on a replacement for the M57727 brick and wonder if anyone has used it and if so, does it work?

The replacement part is a Toshiba RA30H1317M and I originally bought this for my FT-736R. The M57727 is also used in other rigs such as the TS-711 and its ilk. I reproduce the info below from GH Engineering on how to install because the new part is not pin for pin compatible. I do not fancy doing this myself because I do not have the knowledge nor equipment. Does anyone know an emporium I can send it off to because i also want it to be serviced at the same time.

GH Engineering below:

Notes on using RA...series PA modules as a replacement for obsolete M5xxxx and M6xxxx series modules.

Introduction: Mitsubishi stopped all production of the M5xxxx and M6xxxx series PA modules around 2004. Therefore, the entire M5xxxx and M6xxxx series of PA modules are now obsolete; replacement modules are becomming increasingly difficult to source.

Mitsubishi have a competely new range of PA modules using MOSFET technology instead of the older bipolar technology. The new modules have part numbers of the form RAxxYppqqM where :-

xx is the nominal output power in watts
Y is the supply voltage code - N, M or H
pp and qq represent the lower and upper frequency ranges in 10s of MHz.
M indicates that the frequency is in MHz.

Example - RA60H1317M - 60W output, 12.5V supply voltage, frequency range 130-170MHz.

There is one exception which is the RA18G1213G which has a frequeny range of 1240-1300MHz. Also of note is the RA30H0608M which has a frequency range of 66-88MHz.

Differences between the two series of modules

The RA... series modules are intended for new designs; they are not primarily intended as direct replacements for the Mxxxxx series modules. The RA... series have a number of technological improvements over the Mxxxx series, including :-

Wider operating frequency range
Better linearity
Much higher gain
Improved bias requirements
Lower harmonics
Lower cost

Some of these improvements make it difficult, although not impossible, to use the RA.... modules as replacments for the Mxxxx series modules.

The most important differences are :-

i) Bias voltage reduced to 5V (was 9V or sometimes 8V)
ii) Bias pin changed from pin 3 (centre pin) to pin 2
iii) Worse efficiency, resulting in greater current drain and heat dissipation
iv) Much lower levels of drive requied

In detail :-

i) Bias voltage

The bias voltage on all the RA.... modules is nominally 5V, altough this can be varied slightly if required. The bias current required is specified as 1mA maximum, although in practice the current is much less than this. This means that a new voltage regulator will be required giving a regulated 5V bias supply.

ii) Bias pin changed.

With the exception of the M57716 and some Mxxxx modules with an 'R' suffix, the older series modules had the bias supply on pin 3 (centre pin). Pin 2 was connected to Vcc (12.5V). The RA modules have no centre pin, and the bias is now connected to pin 2. Therefore, it will be necessary to cut the existing Vcc track to pin2, and add a wire link from the (now 5V) bias supply to pin 2. It is advisable to leave the existing bias de-coupling components in place.

iii) It is essential to read and understand the datasheet for the particular RA... module used as a replacement. The DC current requirement for many of the RA... modules is higher than for the corresponding M..... series modules, and therefore care must be taken that the DC power supply is able to source this current. In addition, there may be extra heat to dissipate as a result of the lower efficiency. This could be a particular problem for many VHF/UHF transceivers where the heatsink was barely adequate to cool the M...... series module. If an RA.... module is used as a replacement, it may be necessary to add extra cooling, for instance by the use of a fan to force air across the heatsink.

iv) The RA..... modules will be damaged is supplied witth the same level of drive as the M..... modules. The only way to avoid this is to use a fixed attenuator on the input circuit. A pi-attenuator consisting of three 0805 or similar SMD resistors would be suitable. The attenuation value of the attenuator can be determined from the data sheets of both the M.... module being replaced and the RA.... module replacing it.


Other considerations


The RA.... modules are static sensitive; full static handling procedures must be used at all stages of handling and construction. This includes the use of a soldering iron with a grounded tip - and which needs to be tested beforehand.

Many of the RA... modules have a recess in the flange; it is important to apply the correct amount of thermal paste in the recessed area, with none on the outer parts of the flange. Note that the outer edges of the flange are not parallel. This is a design fault, but is unlikely to be rectified by Mitsubishi. The consequence of this is that the depth of the centre section of the flange is far greater than the figure given in the data sheet (0.09mm). The remedy is to apply sufficient thermal paste to fill the centre section. Note however that no paste should be applied to the outer edges of the flange which touch the heatsink. It is important that the ground connection to the module, which is via the mounting screws, is as good as possible, and any contamination of the screw threads by thermal paste could compromise the grounding and lead to instability. This is particularly important on the RA18H1213G, which is the highest frequency module, where cleanliness of the mounting threads is paramout.


For the RA.... modules that have a flat flange, a uniform, very thin layer of thermal paste is required.


For more information please contact GH Engineering.
TIA for any help or advice,
Ellis

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Mon Feb 22, 2021 1:02 pm
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 Trio 9130 and intermittent output 
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Post Re: Trio 9130 and intermittent output
Sorry, re read it, not relevant

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Mon Feb 22, 2021 3:16 pm
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 Trio 9130 and intermittent output 
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Post Re: Trio 9130 and intermittent output
Sangoma wrote:
Sorry, re read it, not relevant



Is it no good as a replacement?
Ellis

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Mon Feb 22, 2021 6:39 pm
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 Trio 9130 and intermittent output 
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Post Re: Trio 9130 and intermittent output
G1PDA wrote:
I have a Trio 9130 with off/on RF output when I key the mic - it happens in FM & SSB. I have traced the RF output up to the driver and all is well.


I had one many years ago that did exactly the same thing.

Before you discard the original you might want to try and remove the plastic cover and check for dry joints inside. I 'think' from memory that the cover was epoxied on around the edges, but it was possible to crack it free from the metal back plate/heatsink.

I was able to repair mine with just a few seconds of soldering, and the PA module was still working when I sold it around four or five years after the repair was done.

73, Mark...

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Mon Feb 22, 2021 8:53 pm
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 Trio 9130 and intermittent output 
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Post Re: Trio 9130 and intermittent output
G0KZZ wrote:
G1PDA wrote:
I have a Trio 9130 with off/on RF output when I key the mic - it happens in FM & SSB. I have traced the RF output up to the driver and all is well.


I had one many years ago that did exactly the same thing.

Before you discard the original you might want to try and remove the plastic cover and check for dry joints inside. I 'think' from memory that the cover was epoxied on around the edges, but it was possible to crack it free from the metal back plate/heatsink.

I was able to repair mine with just a few seconds of soldering, and the PA module was still working when I sold it around four or five years after the repair was done.

73, Mark...

I have done the same with Ascom 550 PA blocks, they often go intermittent on transmit, usually if you can get the block apart, internally you find one of the small gold plated flying leads has come intermittent unattached from its connection.
With a bit of care and a fine point hot iron, (you need a good hot one as the blocks heat sink substrate sucks the heat out of the attempted new connection as fast as you apply it! :D ), you can solder blob it back in place again, and get a few more years life out of it.
Trying to find a replacement block, is like acquiring unobtanium at times! :D

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Tue Feb 23, 2021 7:38 am
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 Trio 9130 and intermittent output 
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Post Re: Trio 9130 and intermittent output
Thanks to all for replying.

I did 'pop' the cover and carefully examined the inlayed onto ceramic tracks with a bright light and magnifying glass - could not see anything amiss. I also use a couple of field strength meters one metre away from my rig. I use the first one to check the driver trannie and the field strength stays constant all the time I key up. The second field strength meter was placed about 4 metres away and I use this to check the output from the M57727 ; these meter readings are up and down like a yoyo whilst the driver trannie meter stays constant.

I had a pm chat with sangoma and he has put me onto another module. When I replace my existing one I will report back.
Once again, thanks for all replies.

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Tue Feb 23, 2021 6:11 pm
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 Trio 9130 and intermittent output 
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Post Re: Trio 9130 and intermittent output
Shame that it was not obvious inside the chip, would have been a nice quick fix of course.
It could be a crack in the substrate, they can be so fine that even with a good magnifying glass they are very hard to see.
Good news on the replacement one though, there are still quite a lot of these oldie but goodie radio's around, they were very popular for good reason.
Worth posting your results and any mods needed to get the new one in and running, with all of these radio's now getting on a bit I am sure the info would be very useful to other owners of them, should theirs one day start to play up! :good:
I have always liked the old 9130.

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Wed Feb 24, 2021 6:35 am
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 Trio 9130 and intermittent output 
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Post Re: Trio 9130 and intermittent output
G0BHD wrote:
Shame that it was not obvious inside the chip, would have been a nice quick fix of course.
It could be a crack in the substrate, they can be so fine that even with a good magnifying glass they are very hard to see.
Good news on the replacement one though, there are still quite a lot of these oldie but goodie radio's around, they were very popular for good reason.
Worth posting your results and any mods needed to get the new one in and running, with all of these radio's now getting on a bit I am sure the info would be very useful to other owners of them, should theirs one day start to play up! :good:
I have always liked the old 9130.


Sorry, just noticed this.

Yep, I'll have a go but I am more familiar with antennas and propagation. The insides of these things are still a big mystery to me even though I have over 35 years as a radio ham under my belt. The nice thing is though, if I do get stuck and I will, there is plenty of technical expertise and experience on this site to call on.

I've had my FT-736R (with Mutek front ends) for over 25 years (with very little TX use) but at some stage that PA block (M57727) will need to be replaced. My wish list is a Trio 751E or Icom IC-251 (with Mutek front end). To be truthfu,l I prefer analogue over digital yet it seems digital is the future of the hobby for many amateurs. I have always liked the diversity of interests within this hobby of ours. From this location I have almost given up HF because of noise but I started on VHF and will no doubt finish on VHF.

Ellis

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Fri Feb 26, 2021 3:50 pm
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