Yaesu FT 757GX No Lights no Receive No Problem
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- Опубликовано: 23 фев 2020
- Got another Yaesu FY-757GX in for repair. This time there were no lights on the display and no receive. Here is how I fixed it.. I believe it the problem might have been caused by operator error.
I did go back into the radio and do a full alignment but since that procedure has been shown many times before I didn't include it in an already long video. 
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Good to see you back mate. Love Yaesu
Very nicely done. I'm glad for the long video that captured the entire process from start to finish! I just inherited the same radio with a reported problem with the power supply. No details and I haven't powered it up yet but will take this video to heart as I round up documentation and prepare to take a closer look. Trouble shooting will be part of the fun. Thank you for your time and knowledge!
Glad I could help. Good luck.
How did it go?
I learned a lot from this video. I have one of these transceivers good receive but no transmit, acts like a short when I press the mic. I have one of the long plug in wires that is smashed in but it ohms good so believe it is ok. My turn to check mine like you did here. I suspect a bad diode or power transistor. Thanks for the video.
I accidently shorted the 12V from the meter lights to ground. It blew out the trace in the exact same area. Soldered in a bridge and it's good to go! Thanks much de WS4JM
That is such a weak spot. Any extra current will take it out. I guess it could be called a feature, like a fuse.
Picked one of these up for free a few weeks ago at a HAM swap, its demonstrating the very same issues....will probably work on it next week if free time is available....thanks for the video, pointers and talking/walking thru the steps....my troubleshooting skills sux....but I have great determination....sometimes that causes me to fubar things! :) Thanks again! ~Jack, VEG
Good luck. Let us know how it goes. Thanks for watching.
Thanks for this video! I have a FT-757 GX II with a similar problem.
Edit: It was the exact same copper trace that had burned! Thanks for Your help!
Glad it helped. That seems to be a problem with these. Thanks for watching.
Nice repair! Looks like someone had "fixed" that trace before - the other traces had solder mask over them and no solder on them. I like to put a couple of drops of UV glue along my bodge wires to hold them down tightly to the board. I started using UV glue a while back and love the stuff.
It did not show in the camera as well as I could see it but the trace had not been worked on before. There were other signs of repairs inside and a bunch of replaced diodes and caps. I probably should have replaced that trace instead of jumpering it but there was so little room.
Thanks for watching
By long plug in wires I mean the ones you said be very careful with when pulling them out. I hold the socket and use needle nose pliers to pull them and plug them back in after I ohm them. My transceiver came with one smashed.
The way they routed all those wires all over the place makes it so hard to get it back together without smashing at least one. Pay special attention to the wire bundle going into the PA. Thanks for watching. Good luck.
Nice fix
Thanks
Your video reminded me to redo the battery so it is easily changed.
Oh yeah... Subscribed.
Now, if I get this thing running... Do you know the MARS mod?
Is this what you mean? Remove the top cover,locate the small black switch that is located on the edge of the big horizontal board near the back of the main tuning dial, it will be under a bundle of wires.
Flip the switch, and put radio back together.
This allows general coverage.
Good video... My radio has done exactly the same thing...
Did the video help you fix it? Thanks for watching.
@@AERVBlog It might... I'll have a go int h weekend...
@@andygeorge6065 let me know.
@@AERVBlog Turns out my problem was something different and more "Pilot Error" related... MOX and VOX on at the same time, and radio acted like it was completely unpowered... Thanks anyway, but its working now...
@@andygeorge6065 that has caught me too. You know, turning the radio around and such while on the bench and hitting that MOX switch and suddenly the whole radio is dead. Bet you won't let that get you again. Glad it is working. Happy DXing.
I acquired my General ticket last year and I have a used Yaesu FT-757GX and an LK500ZB Amp Supply Amp I inherited from my deceased uncle KK4LZ. I have read the FT-757GX Operator's manual and I am not sure which connection I plug the rca jack in on the back of the radio. Does the LK500ZB have a relay coil voltage over 50 volts? According to the manual the internal control relay in the FT-7 5 7GX is not designed to handle high voltage (above 50 V) or current (above 400 mA). Can you advise how I connect the radio to this amp?
Thank you
Please contact me at aervblog@gmail.com
Thank's for the Video and disassembly on the unit. I have a FT-757GXII. Possible trace problem as you and Drummelskrudd had, Now to look into it. Thank's Scott from Colorado.
Good luck and be sure to let us know how it turns out. Thanks for the good words.
@@AERVBlog It ended up being a burned trace, Inside the PA unit In the area of RL01. Jumpered the trace and i had power everywhere. But your video was very helpfull to trace the power. Thank's again,
@@slingslingbinks glad I could help in some way. Happy DXing.
My radio that needs help is a Yaesu ft-757gx. Does anyone know what the power Transistors located on the PA board are called? Anyone know where I can buy them? Or does anyone know where I can buy a PA board for it?
TOSHIBA 2SC2879
I been working on a 757 and the 7808 and a1012 on the pa board were shot and c24 blown up there too. I replaced all the tantalums on the pa and the 7808 and a1012 and it now fires up and receives but on tx theres no output and no on the air light. after seeing this video with the on air light I checked mine and no light. any ideas? thanks
also on FM theres still hiss on TX like its not switching to tx but it mutes on the other modes
I dont have a magic fix for you but I would check all the little switching diodes. They cause all kinds of problems. There are a bunch of them so be patient. You don't have to take them out in almost all cases but if you aren't sure remove one end. Good luck and thanks for watching.
HELLO FRIEND, MY 757GX IS WITH LOW VOLUME OF FM RECEPTION, WOULD YOU HAVE ANY IDEA OF WHAT IT CAN BE?
Boy, that could be a lot of things. Volume on FM is a factor of frequency shift. If the person transmitting is not swinging the frequency 5KHz your volume will be pretty low. Or the FM discriminator could be off tune and that would do the same thing.
Could it be that the backup battery is running out, there is no monitor at all or there is no connection?
In this case the backup battery was good. That really amazes me though.
Hi! I have an offer for one 1986 757gx, working condition for around $250. Is it a good buy for a working radio which was extensively used?
That is a hard one to answer. On one hand I love the 757GX . It has features that make it better than any other radio in its price range but on the other hand they are old and require maintenance. That is a pretty good price but only if you are able to keep it running. The diodes will fail. The PA will probably die and sooner or later the caps will need to be changed. I would base my decision on that.
Thanks for watching.
Thanks, on that advice I have decided to go with Bitx40 QRP radio! Couple of 100 bucks there are good and new radios!
My old 757 the display board or cpu has gone cannot find either to try
Have you checked the voltages like in the video? It seems that trace does loose sometimes. Watch the video at 24:51 or so.
My 757 rotating dial wheel is jammed, the frequency is locked even when I can get it to rotate with difficulty, and nothing seems to loosen it. I've had it apart inside and out, but find no solution...any ideas?
You would be amazed at how locked up the tuning shaft can get from dried grease and dust. Make sure that is turning. There are a few videos on youtube about it.
@@AERVBlog Thanks for the response, and I've tried to get the whole dialing unit out, but find no way to do so due to my inability technologically. I'm 87, have unskilled fingers, and I can't find somebody to do the repair. Also, the cost in today's economy makes it more reasonable to throw the rig away and buy another used one. I like dials and buttons, not menus. When you've been in love with the old equipment for years and can't keep up with the new technology, you don't have much choice.
sorry for the rant. I'm just so frustrated.
Iam having a problem with it no tx and no display just reads rrrrr
There are a lot of things it could be. I have not seen that before. Sorry.
Pregunta que es lo que puentio el amigo tengo uno igual creo que está laburando la etapa de memorias
I am not sure I understand. Please try again.
Mine transmits on fm no receve sounds like the same issue i have with the fm
If you aren't getting any sound out of it at all check the audio amplifier chip.
@@AERVBlog i have read that the frount end that the swiching diodes are leaking the chip thinks it closed and i can transmit but the receive is like a little hiss like the sqwelch is left all the way up. Thier on the rf board. I have the information its a row of diodes then thiers one left to also to change i have to check the voltages chances are ones open the rest are leaky. The original diodes that belong to this radio thiey dont have enymore in stock it was from nte they no longer make them you can use 1n4148 ive read that but when i do this iam going to check everything before i do it .👍
@@ATOMSHAMRADIO that is correct. There are a bunch of diodes on that board and they do go bad. 1N4148 will work. Good luck. Let us know how it turns out.
@@AERVBlog its going to be awhile i just dont have fm i use the ssb modes on the hambands i rarely use fm unless 10 meters has reapeters which i haven't used in years. Over all that radio is very clean not molested the only thing i like to send it out to get it aligned to factory specs.
Wow tomorrow i open my radio maybe is the same problem. give me lucky 73
So.... how did it work out?
@@AERVBlog nop. i change the radio.
I had the 757GX and the 757GX2. Both crap radio's.
That's not fair. For their day the were pretty good. They offered a lot of features. It was still early in the all transistor Era especially in the RF power amp but I still think they did a good job. Receiver wise they rival anything new without DSP.
@@AERVBlog Receiver wise they rival anything without DSP you said? I own a TS450 and as you know it has no DSP either. But put both versions of the 757 next to it and find out which one is deaf, 73s
Go bye bye
Yes. Unfortunately it did, much later. Just too many old parts. Hate to admit it though.
Poor camera
Sorry about that. If you have a better one you would like to donate please feel free.
Too much background noise.
I have a constant 9 noise level here. It is awful!
Or are you talking about the noise in the shop. I have fixed some of that but most of my equipment is old and has big fans inside. Thanks for watching.
@@AERVBlog I tried several times to hear what you called the board where the external power comes in. I had just bought a Yaesu 757 gx and though it was said to be in excellent condition... The moment power was applied it smoked. I am unsure if it is this power board or another board. Now I must try to diagnose this on an exceedingly limited budget. So I am trying to see exactly what each board is named before I try to purchase one or more.
@@terryglenweaver sorry you couldn't hear that. Like I said I am working on getting rid of noise. That board is called the PA board. It is mounted in the top case half. Can you see what smoked and where is it located?
@@AERVBlog I have not yet begun enough disassembly. I merely took a look at the component side of the board. I figure when I examine the trace side I will possibly find where all that some came from.
When I take the power plug jumper off and apply voltage it makes a continuous clicking sound but no smoke. Of course, no lights or anything else either. I plan on unhooking everything but the PA board (power board) then applying voltage. I am just hoping the short did not ruin every board in the radio.