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So, I was out portable today with the X5105, all went well, came back to the car, plugged the radio into the 12v cigar socket (as I have done a thousand times before), this time,though, the in line fuse blew immediately.
I got back home, put the X5105 on the power supply and it shuts down the 3A power supply as soon as it is plugged in.
Taking it apart, it is well out of warranty, I have traced the fault to the middle PCB labeled X5105 base board v2.01, it is dead short across the power supply.
After taking off various likely parts that would draw any kind of current i.e. rf transistors, several electrolytic caps,3 big SMD diodes, i've narrowed it down to one specific part of the pcb.
Below the Lipo battery socket is two seperate circuits, they look very similar, each has a 8 leg SMD device on , the top one of the two, if I feed the PCB with a current limited supply, after several minutes gets really hot, the bottom one does not.
I can not find what the device is, they are labeled 1A JRH, which I cannot seem to find a likely device with that package on the www. 
I have circled the device in red above, if anyone can help, i'd be grateful.
Tony G1HMO
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Tony,?
To my knowledge there are no schematics available, however those square inductors would indicate that chip is a DC to DC converter device.
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On Mar 20, 2022, at 11:30 AM, Tony G1HMO <tonyg1hmo@...> wrote:
? So, I was out portable today with the X5105, all went well, came back to the car, plugged the radio into the 12v cigar socket (as I have done a thousand times before), this time,though, the in line fuse blew immediately.
I got back home, put the X5105 on the power supply and it shuts down the 3A power supply as soon as it is plugged in.
Taking it apart, it is well out of warranty, I have traced the fault to the middle PCB labeled X5105 base board v2.01, it is dead short across the power supply.
After taking off various likely parts that would draw any kind of current i.e. rf transistors, several electrolytic caps,3 big SMD diodes, i've narrowed it down to one specific part of the pcb.
Below the Lipo battery socket is two seperate circuits, they look very similar, each has a 8 leg SMD device on , the top one of the two, if I feed the PCB with a current limited supply, after several minutes gets really hot, the bottom one does not.
I can not find what the device is, they are labeled 1A JRH, which I cannot seem to find a likely device with that package on the www. 
I have circled the device in red above, if anyone can help, i'd be grateful.
Tony G1HMO
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Joe, thank you for that, I did suspect they were voltage regulators of some kind as the tracks around the IC were quite thick, suggesting a reasonable current carrying capacity. I found a photo on the fccid.io page showing the internal pcb's, it looks like a pre-production model but the interesting bit is this    Which shows two regulator sub pcb's one is 8v and the other, which is the one that gets hot in my radio is 3v3. Just need to find out what the device is now, which is proving to be quite a challange. Tony G1HMO
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Extra bit of info, i've removed the suspect 8 pin device, the high current draw has now gone, nothing gets hot, so it's definately a duff device, still no luck in finding what it is though, i'll email Xiegu support but having had dealings in the past, they were not helpful at all.
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Just a hunch: The G90 has a similar voltage regulation system. The schemos are ¡°out there,¡± maybe in the G90 group files area. You might want to check. There¡¯s a fellow in Romania ¡ªwhose call I can¡¯t remember ¡ªhas replaced the G90 VRs with better devices. So that¡¯s another take.?
Too bad Xiegu has (a) no outside repair facility & (b) a typical Maoist secretive view of providing documentation & help. I figure my two Xiegu boxes die, I¡¯ll still have the cheapo varios clones of the DL2MAN (tr)uSDX boxes toQRP with.?
Nils / W8IJN ?
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Try this:
Also :
YO3HJV has more info on his website.
It appears the VRs are different. Worth a stab anyway.?
Nils / W8IJN?
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The G90 is completely different unfortunately, I checked that initially as I have a G90 and the schematics!
But.....
I have made progress, having removed the duff regulator, confirmed that there was no short on it's output, I soldered a thin wire onto the output pad where the Ic came from, then fed this with 3.3v from my variable supply.
With 12v on the main radio, everything works fine,? the radio powered up and tx / rx no issue, for info, the 3.3v rail draws about 400mA.
Knowing the radio was ok apart from the regulator, I gave up trying to find out what the regulator was, and decided it may be quicker to just fit a dedicated 12v to 3.3v buck regulator, I looked at the Pololu modules, which I have used before, they are great, but cannot get a 3.3v one in the UK for love nor money.
So, I looked on Ebay UK for a 3.3v regulator module, there are loads of linear ones using an LM117, but some swicth mode ones too, then I saw this?
Which unbelieveably I think uses the same device that the X5105 uses, certainly has the same package type, zooming in on the pcb, the SMD type number is also 1A, and more importantly, the pinouts 'look' very similar, if not identical, it has the enable pin on the board too.
So I have ordered a few, when they arrive, i'll check the layout iof the PCB to confirm Vin Vout and EN are on the same pins, then I plan to remove the IC from one, and try it in the X5105, I am 100% convinced it is the same IC.
If it works, brilliant, I have a few spares, if not i'll remove all the SMD bits around the regulator in the X5105 and fit the new module in place of them.
Expect a further update later in the week when the modules arrive.?
Tony G1HMO
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Ok, update on the X5105, the modules from Ebay, whilst very nice, the IC looks the same but doesn't work when just the IC is fitted into the Xiegu.
It has a very similar type number stamped onm top, but there is no volts out of it whatsoever.
I was about to remove all the SMD bits around the old regulator in the radio and fit one of the entire PCB's in its place, which would have worked I am sure, but I noticed a tiny white spot on the? X5105 silkscreen, I hadn't noticed it before and as a result, I had assumed the incorrect placement of Pin 1 on the original regulator.
Now having spotted the pin 1 mark, I have also found out teh regulator type, it is an MP 1496S made by Monolithic Power systems, called a 2A 16v 500KHz synchronous step down converter.
The package is an 8 pin TSOT-23, even better Farnell UK have them in stock, the part number is 3357935 and they cost ?1.11 each, shame there is a minimum order of ?30 but I bought several of them plus some other bits i'll probably never use
Here is the datasheet for the regulator if anyone is interested.
So I fitted the IC, and re-assembled the radio, it works perfectly, has been on JS8 call all afternoon.
Interesting that the device has an absolute maximum input voltage of 17v, inside the X5105, it is fed via a big Shottky diode from the power socket but that will only drop 0.2v or so.
I now need to figure out a way to prevent it happening again, possibly some kind of crowbar circuit inside the radio using an SCR and zener to blow the line power fuse if more than 14v goes into the regulators, but that is a project for another day..
Tony
G1HMO
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Tony, Good diagnostic work.? One tool I often use on the bench, is a dissecting microscope.? It helps in inspection of circuit boards, as you describe. Now there are all sorts of USB microscopes that can do similar work.? You do not need a lot of magnification for this purpose.?
--
- Stuart VE3SMF
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Good news Tony, glad you figured it out.
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On Mar 24, 2022, at 9:03 AM, Tony G1HMO <tonyg1hmo@...> wrote:
?Ok, update on the X5105, the modules from Ebay, whilst very nice, the IC looks the same but doesn't work when just the IC is fitted into the Xiegu.
It has a very similar type number stamped onm top, but there is no volts out of it whatsoever.
I was about to remove all the SMD bits around the old regulator in the radio and fit one of the entire PCB's in its place, which would have worked I am sure, but I noticed a tiny white spot on the? X5105 silkscreen, I hadn't noticed it before and as a result, I had assumed the incorrect placement of Pin 1 on the original regulator.
Now having spotted the pin 1 mark, I have also found out teh regulator type, it is an MP 1496S made by Monolithic Power systems, called a 2A 16v 500KHz synchronous step down converter.
The package is an 8 pin TSOT-23, even better Farnell UK have them in stock, the part number is 3357935 and they cost ?1.11 each, shame there is a minimum order of ?30 but I bought several of them plus some other bits i'll probably never use
Here is the datasheet for the regulator if anyone is interested.
So I fitted the IC, and re-assembled the radio, it works perfectly, has been on JS8 call all afternoon.
Interesting that the device has an absolute maximum input voltage of 17v, inside the X5105, it is fed via a big Shottky diode from the power socket but that will only drop 0.2v or so.
I now need to figure out a way to prevent it happening again, possibly some kind of crowbar circuit inside the radio using an SCR and zener to blow the line power fuse if more than 14v goes into the regulators, but that is a project for another day..
Tony
G1HMO
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Congratulations on your success fixing the radio.! ??? I've been following your progress! I own a X5105 also and it's always in the back of my mind that it's going to fail and it'll be a throw away!
Roy WA0YMH
Ok, update on the X5105, the modules from Ebay, whilst very nice, the IC looks the same but doesn't work when just the IC is fitted into the Xiegu.
It has a very similar type number stamped onm top, but there is no volts out of it whatsoever.
I was about to remove all the SMD bits around the old regulator in the radio and fit one of the entire PCB's in its place, which would have worked I am sure, but I noticed a tiny white spot on the? X5105 silkscreen, I hadn't noticed it before and as a result, I had assumed the incorrect placement of Pin 1 on the original regulator.
Now having spotted the pin 1 mark, I have also found out teh regulator type, it is an MP 1496S made by Monolithic Power systems, called a 2A 16v 500KHz synchronous step down converter.
The package is an 8 pin TSOT-23, even better Farnell UK have them in stock, the part number is 3357935 and they cost ?1.11 each, shame there is a minimum order of ?30 but I bought several of them plus some other bits i'll probably never use
Here is the datasheet for the regulator if anyone is interested.
So I fitted the IC, and re-assembled the radio, it works perfectly, has been on JS8 call all afternoon.
Interesting that the device has an absolute maximum input voltage of 17v, inside the X5105, it is fed via a big Shottky diode from the power socket but that will only drop 0.2v or so.
I now need to figure out a way to prevent it happening again, possibly some kind of crowbar circuit inside the radio using an SCR and zener to blow the line power fuse if more than 14v goes into the regulators, but that is a project for another day..
Tony
G1HMO
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Dear Friends
As a dedicated technician who has been repairing radios of many brands for years, I find it a shame that in 2022 there are manufacturers who refuse to publish technical documentation on their equipment. Sooner or later the transceivers will need repair and some will end up in the trash without documentation. We should send a strong signal and no longer consider the products of these manufacturers. I know this is a small consolation for the colleagues who already have this problem. Nevertheless, we should spread this problem as far as possible, so that perhaps a certain pressure arises with the manufacturers.
Best 73, Giovanni, HB9EKH
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Giovanni, I have to agree with you and at times I'm ashamed of myself for having boughten the radio and been apart of the support of that mentality. The elephant in the room is the fact that the Chinese are so willing to steal intellectual property that their mindset is that they won't provide any information about their own products, for fear someone will do the same thing to them.
Roy WA0YMH
On Thu, Mar 24, 2022 at 12:18 PM Giovanni D < gda@...> wrote: Dear Friends
As a dedicated technician who has been repairing radios of many brands
for years, I find it a shame that in 2022 there are manufacturers who
refuse to publish technical documentation on their equipment.? Sooner or
later the transceivers will need repair and some will end up in the
trash without documentation.? We should send a strong signal and no
longer consider the products of these manufacturers. I know this is a
small consolation for the colleagues who already have this problem.
Nevertheless, we should spread this problem as far as possible, so that
perhaps a certain pressure arises with the manufacturers.
Best 73, Giovanni, HB9EKH
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Roy, that is exactly the way I think, certainly I doubt that I will now buy another Chinese radio that schematics are not avialable for.
I did email Xiegu tech support twice requesting the part number for the regulator that had died, they never even replied to my emails, thinking back, I also emailed them when I had an X107G, they never replied to that email either!
Tony?
G1HMO
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Hello Tony,
In your opinion are we ever going to see a finalized firmware version for the X5105? I know that there¡¯s a lot of hype and activity surrounding the ¡®6100¡ have 5105 owners been forsaken?
Thank you Howie WA3MCK
On Thu, Mar 24, 2022 at 12:03 PM Tony G1HMO < tonyg1hmo@...> wrote: Ok, update on the X5105, the modules from Ebay, whilst very nice, the IC looks the same but doesn't work when just the IC is fitted into the Xiegu.
It has a very similar type number stamped onm top, but there is no volts out of it whatsoever.
I was about to remove all the SMD bits around the old regulator in the radio and fit one of the entire PCB's in its place, which would have worked I am sure, but I noticed a tiny white spot on the? X5105 silkscreen, I hadn't noticed it before and as a result, I had assumed the incorrect placement of Pin 1 on the original regulator.
Now having spotted the pin 1 mark, I have also found out teh regulator type, it is an MP 1496S made by Monolithic Power systems, called a 2A 16v 500KHz synchronous step down converter.
The package is an 8 pin TSOT-23, even better Farnell UK have them in stock, the part number is 3357935 and they cost ?1.11 each, shame there is a minimum order of ?30 but I bought several of them plus some other bits i'll probably never use
Here is the datasheet for the regulator if anyone is interested.
So I fitted the IC, and re-assembled the radio, it works perfectly, has been on JS8 call all afternoon.
Interesting that the device has an absolute maximum input voltage of 17v, inside the X5105, it is fed via a big Shottky diode from the power socket but that will only drop 0.2v or so.
I now need to figure out a way to prevent it happening again, possibly some kind of crowbar circuit inside the radio using an SCR and zener to blow the line power fuse if more than 14v goes into the regulators, but that is a project for another day..
Tony
G1HMO
-- "Quis custodiet ipsos custodes?"
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Do you think there is a time period when the FCC releases the schematics provided by the manufacturer when the device was certified?
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Tom
AE5NF
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I wholeheartedly agree.? My 5105 is now dead.? No recourse for repair.? I will never buy a Chinese radio again at these prices.?
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Have they ever done that before?
It seems very unlikely to me that they would be allowed to do that.? If they do have schematics, which seems unlikely to me, the drawings would still be intellectual property of Xiegu.
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Doug, K8RFT
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I have no idea¡ maybe we need to find someone that can send a Chinese language email to the company asking for schematics.
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Tom
AE5NF
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Try to contact , they are official distributors for Europe, maybe they can offer you a solution for your problem. I bought my X 5105 from them and they was very kind. Perheps they would contact the producer for you.
I have no idea¡ maybe we need to find someone that can send a Chinese language email to the company asking for schematics.
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Tom
AE5NF
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Joel Caulkins/N6ALT
Nils R. Bull Young
Howie WA3MCK
Larry