query on any good online course or portal for repairing 5 watt radio transceiver units please?

[bcoleman1]

Hi Hope all is well. query on any good online course or portal for repairing 5 watt radio transceiver units please?
I am researching online at present and found a good repair course on Udemy website for electronic repairing units, however
I am trying to find a course, online or part-time in Dublin on repairing radio transceiver units.
e.g. need to know how to fix the following:
1) no tx, no rx
2) tx stuck in low power
3) pa issues on pa component
4) vco or voltage issue no volts

Units are AES model 7350 and are used as fire and intruder alarm units on a radio mesh network.
appreciate any help or support please/

Thank you.

 

[ladn]

Units are AES model 7350 and are used as fire and intruder alarm units on a radio mesh network.
appreciate any help or support please/

Welcome to RR.

I can't recommend any specific courses, but have you checked if the manufacturer has service literature available? If so, this would give you some idea of the technical acumen needed to diagnose and repair their hardware. Service literature will also specify the instrumentation required to repair said equipment. Hardware, such as a service monitor, can be quite pricey and you'll want to consider your return on investment (in equipment, training and procuring parts) versus outsourcing the repair.

 

[bcoleman1]

Welcome to RR.

I can't recommend any specific courses, but have you checked if the manufacturer has service literature available? If so, this would give you some idea of the technical acumen needed to diagnose and repair their hardware. Service literature will also specify the instrumentation required to repair said equipment. Hardware, such as a service monitor, can be quite pricey and you'll want to consider your return on investment (in equipment, training and procuring parts) versus outsourcing the repair.

Thank you and appreciate the feedback. However the supplier AES has all such specific doc. re: repair work of their units under lock and key due to IP rights. This I can understand, if there were resources online that may aid in repairing similar type of problems encountered with 5 watt internal radio transmitter components be great to find them? I tried searching on youtube.com and udemy.com in the meantime, did not find an exact match, but will let you know if the one I found on youtube is of help. Thanks again. Hope all is well. rgds, Barry p.s. I have a Motorola spectrum analyzer in the office dated early 1990s, trying to find my way around it at the moment, takes bit of getting use to as there seems to be other more modern versions of the same out there, which are more user friendly.

 

[davidgcet]

a spectrum analyzer is no good for any of the listed issues. you need a calibrated full service monitor, voltmeter, and most likely the manufacturer alignment software/cables at minimum. a used service monitor that has been calibrated is likely around 3000 USD or more, waaay more if it needs any special software options. unless you will be repairing a lot of these you will be better off finding a vendor approved repair center or sending them to the vendor direct for repair if they will do that. radio repair is not something you jump on line and figure out how to do, at least not without a big budget and a good base knowledge of electronics and rf.

 

[ladn]

... the supplier AES has all such specific doc. re: repair work of their units under lock and key due to IP rights....if there were resources online that may aid in repairing similar type of problems encountered with 5 watt internal radio transmitter components be great to find them

Here in the States, that's called "right to repair" and is a contentious issue between users and manufacturers.

YouTube "experts" and "teknichuns" can be of questionable competence. Other users or user groups may be better sources.

Also, what about parts availability? I'm not familiar with this equipment, but if it's reasonably new it probably is fabricated with SMD (Surface Mount Device) technology which itself requires specialized equipment.

 

[bcoleman1]

a spectrum analyzer is no good for any of the listed issues. you need a calibrated full service monitor, voltmeter, and most likely the manufacturer alignment software/cables at minimum. a used service monitor that has been calibrated is likely around 3000 USD or more, waaay more if it needs any special software options. unless you will be repairing a lot of these you will be better off finding a vendor approved repair center or sending them to the vendor direct for repair if they will do that. radio repair is not something you jump on line and figure out how to do, at least not without a big budget and a good base knowledge of electronics and rf.

thank you for the feedback, appreciated. Apologies, I have a Motorola service monitor in the office which was calibrated and working - just need to figure out how to use it now. Found 48-50 page manual on how to use it online. Thanks again.

 

[prcguy]

a spectrum analyzer is no good for any of the listed issues. you need a calibrated full service monitor, voltmeter, and most likely the manufacturer alignment software/cables at minimum. a used service monitor that has been calibrated is likely around 3000 USD or more, waaay more if it needs any special software options. unless you will be repairing a lot of these you will be better off finding a vendor approved repair center or sending them to the vendor direct for repair if they will do that. radio repair is not something you jump on line and figure out how to do, at least not without a big budget and a good base knowledge of electronics and rf.

Spectrum analyzer with a 10:1 or 100:1 scope probe is great for tracing RF in transmitters and receivers, its a very useful tool. I've been using a TinySA for troubleshooting lately.

 

[davidgcet]

true, but your level of experience is worlds beyond his. without proper training a SA is useless to many folks for the things he described. now that he says it is a service monitor that does change things, but as anyone that has worked professionally repairing 2 way will tell you that is only part of the battle. not to sound negative, but without the actual manuals and no knowledge of how to repair radios he is better off paying to have it done. one cannot just use basic generic manuals to troubleshoot modern radios.

 

[davidgcet]

that being said, if you understand the circuit and they have physical tuning points you may can resolve some minor power issues. most tuning and alignment now though is all softpots adjusted via the software alignment tool. you may can fix things like a cold solder/broken trace and do some minor component replacement assuming you can identify and obtain the parts. maybe able to use some of the worst units as parts donors, just kinda depends on what is wrong. also some stuff has to be soldered with the proper air solder, but a lot can still be done with a very fine tip iron. it all depends on the component and your soldering skills.

anyway, i take it from your wording you don't have a lot of experience in this. if you do i apologize. my intent is just to clarify that a generic video won't tell you specifically how to repair your units. every manufacturer has their own layouts and components. so a good base knowledge is mandatory to shotgun troubleshoot.

 

[flametamer]

... you may can fix things like a cold solder/broken trace and do some minor component replacement assuming you can identify and obtain the parts....

And IF it's not in the middle of a multi-layer pcb.

Dt

 

[freddaniel]

The service manual is available on the FCC website and on other websites that republish public FCC Type Acceptance data. One site which has the UHF version is FCC ID L9N-7350UE5 and the service manual is listed as the user manual. The radio is made by a manufacturer in Taiwan called Hermes Electronics.

It may be cheaper to simply buy replacement boards from Taiwan. Great care must be taken to not identify you are bypassing AES and their service operations. See attached screen capture of Radio Test Report. Good luck.

 

[bcoleman1]

The service manual is available on the FCC website and on other websites that republish public FCC Type Acceptance data. One site which has the UHF version is FCC ID L9N-7350UE5 and the service manual is listed as the user manual. The radio is made by a manufacturer in Taiwan called Hermes Electronics.

It may be cheaper to simply buy replacement boards from Taiwan. Great care must be taken to not identify you are bypassing AES and their service operations. See attached screen capture of Radio Test Report. Good luck.

Many Thanks Fred for the very informative feedback. The radios we use are identical however we use VHF as opposed to the UHF standard here in Ireland. I did try ask AES in the past year for schematic diags. , however all that info. is kept under lock and key due to IP rights, which I can understand. The RF boards are mainly where we see the issues, most common issues are with PA , sometimes VCO, both components are integrated onto the RF board. Found out from my predecessor, a man with 40 yrs + radio eng experience that the rubber duck like antennaes whips cause the pa component to go sooner in the radio transmitters. Trying to find another comparable 3db Antennae instead for e.g. extended antennae ground to a square metal plate which I find good in commercial premises or home attics. Many Thanks again. Would it be worth a shot to try contact the Co. in Taiwan directly to get a quote on for example a batch of 10 or 20 RF boards for the same radio transmitter? Rgds, Barry - work for alarm monitoring Co btw.

 

[bcoleman1]

true, but your level of experience is worlds beyond his. without proper training a SA is useless to many folks for the things he described. now that he says it is a service monitor that does change things, but as anyone that has worked professionally repairing 2 way will tell you that is only part of the battle. not to sound negative, but without the actual manuals and no knowledge of how to repair radios he is better off paying to have it done. one cannot just use basic generic manuals to troubleshoot modern radios.

thanks for the feedback- new to RF eng only 20months in current role radio mesh alarm units btw..

 

[bcoleman1]

Spectrum analyzer with a 10:1 or 100:1 scope probe is great for tracing RF in transmitters and receivers, its a very useful tool. I've been using a TinySA for troubleshooting lately.

Many thanks - see a lot of good review on Tiny SA Ultra online on youtube etc, thanks again for great tip, appreciated. Rgds,Barry

 

[freddaniel]

Consider investing the time to photograph both sides of the RF boards and then use a high impedance voltmeter and a spectrum analyzer with RF probe to determine the proper working DC voltage and RF levels of a good working board for reference. Record these reading on the photos with a photo editor. Then you can troubleshoot bad boards far easier. With some effort, you can create a block diagram showing how much RF gain or loss occurs in each stage. You may even be able to sell the information to other shops who need to repair the same boards. Older superheterodyne designs are easy to troubleshoot as they are not complex. Mostly gain blocks. After making sure there is enough local oscillator signal at the mixer, then inject a "reference" signal into the receiver, like 100 uV and follow the signal through the front end, mixer and IF to the detector. The problems practically leap out at you. Like instead of 12 dB gain, you see a 35 dB loss.

To learn more about RF troubleshooting, consider buying old Motorola or GE radios on Ebay that have manuals and schematics available. Then use the same procedure to follow the signal, with the help of real quality schematics. Then buy bad ones and try your hand at fixing them. Everything you need to learn is on the Internet, the trick is finding it. So much to learn and so much fun.

CAUTION: not all scope probes are the same or work well on RF above several MHz, so seek advise and research. Same goes for high Impedance volt meters. You can tell a good meter and probe because it does not reduce the signal passing through, while sampling.

 

[prcguy]

Many thanks - see a lot of good review on Tiny SA Ultra online on youtube etc, thanks again for great tip, appreciated. Rgds,Barry

I was recently asked to visit a local trunked radio site and when we got there some unexpected problems were found. I was not planning on troubleshooting anything but I did have my Tiny SA with me which was able to verify no receive signals from a master rx front end to the receivers and I could also generate RF signals to the receivers to verify they were working. I wont go into what problem was found but it was great to have something with me that can do measurements on both transmitters and receivers within limits of course. I find the RF generator in the TinySA is pretty close so you can get a good idea if a receiver is meeting spec, etc.

I also recently used the TinySA to troubleshoot a 2.4GHz wireless mic problem at a church and found the antenna distribution system was toast. I also used the TinySA to verify the repairs made and the system was working ok.