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I have a 817 I am working on that I picked up at a flea.
- on battery, when POW-ON the display briefly starts (solid pattern on LCD) and shuts off (and I hear a relay click)
- on external power, the rig does nothing (and it appears there maybe short -- supply shuts off)
Anyone seen this before? I probed around the power connector and it seems ok I also checked the MAIN board top and bottom and I don't see any craters. On battery, when I power up I seem to get a good 5V at the display before it shuts off. b
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Also, what fault would cause a VOM voltage reading of 13.8V from the DC barrel (-) to the 817 metal case? (same radio) Do I have a shorted cap?
b
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Hello Bill
I do not have a circuit (schematic) for the 817 here but I do know that the much earlier FT290 and FT690 had a reverse polarity diode in the negative pole of the DC power connector.
If the FT817 is similar, I would investigate the health of that, or any other, reverse polarity protection circuit / device.
Hope this helps
Denis VK6AKR
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On Friday, October 21, 2022, Bill W1PA < w1pa@...> wrote: > Also, what fault would cause a VOM voltage reading of 13.8V from the DC barrel (-) to the 817 metal case? (same radio) Do I have a shorted cap? > > b > _._,_._,_ > ________________________________ > Groups.io Links: > > You receive all messages sent to this group. > > View/Reply Online (#113242) | Reply To Group | Reply To Sender | Mute This Topic | New Topic > Your Subscription | Contact Group Owner | Unsubscribe [ kanekobrown1@...] > > _._,_._,_
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b,
Is the VOM reading with the power connector plugged into the FT817.
If you do then I would think the connector has lost it's connection to the FT817 ground/neg supply connection. If not in the FT817 then I would be concerned if the cable connections are reversed and the fT817 has another path to ground.
73, ron, n9ee/r Ron Wright, N9EE/R Hernando Co ARES EC
Spring Hill, Florida also n9ee55@...
On Thursday, October 20, 2022 at 08:19:41 PM EDT, Denis Brown <kanekobrown1@...> wrote:
Hello Bill
I do not have a circuit (schematic) for the 817 here but I do know that the much earlier FT290 and FT690 had a reverse polarity diode in the negative pole of the DC power connector.
If the FT817 is similar, I would investigate the health of that, or any other, reverse polarity protection circuit / device.
Hope this helps
Denis VK6AKR
On Friday, October 21, 2022, Bill W1PA < w1pa@...> wrote: > Also, what fault would cause a VOM voltage reading of 13.8V from the DC barrel (-) to the 817 metal case? (same radio) Do I have a shorted cap? > > b
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with power plugged in ? --- yes.
If I remove the power and use the battery, the voltage readings seem correct.
In the original post I was measuring from the 817 case to the 13.8 line on the main board and getting 0v (because relative to the DC barrel, they are both 13.8 -- same potential)
b
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EA4GPZ has a great article on replacing the Internal fuse within the FT817.
I damaged my own fuse when I reverse polarised the unit a couple of years ago. Kindest regards,
Doug Jackson
ph: 0414 986878
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Be nice to your parents.
Go outside and do something awesome - Draw, paint, walk, setup a radio station, go fishing or sailing - just do something that makes you happy. ^G ^G ^G ^G ^G ^G ^G ^G- In more laid back days this line would literally sing ^G ^G ^G ^G ^G ^G ^G ^G
On Fri, 21 Oct 2022 at 12:06, Bill W1PA < w1pa@...> wrote: with power plugged in ? --- yes.
If I remove the power and use the battery, the voltage readings seem correct.
In the original post I was measuring from the 817 case to the 13.8 line on the main board and getting 0v (because relative to the DC barrel, they are both 13.8 -- same potential)
b
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Yeah the fuse next to the three electrolytics was the first thing I checked. It's conductive.
On Oct 20, 2022 9:26 PM, Doug Jackson <doug@...> wrote: EA4GPZ has a great article on replacing the Internal fuse within the FT817.
I damaged my own fuse when I reverse polarised the unit a couple of years ago. Kindest regards,
Doug Jackson
ph: 0414 986878
----------------------------------------------------------- Just like an old fashioned letter, this email and any files transmitted with it should probably be treated as confidential and intended solely for your own use.
Please note that any interesting spelling is usually my own and may have been caused by fat thumbs on a tiny tiny keyboard. Should any part of this message prove to be useful in the event of the imminent Zombie Apocalypse then the sender bears no personal, legal, or moral responsibility for any outcome resulting from its usage unless the result of said usage is the unlikely defeat of the Zombie Hordes in which case the sender takes full credit without any theoretical or actual legal liability. :-)
Be nice to your parents.
Go outside and do something awesome - Draw, paint, walk, setup a radio station, go fishing or sailing - just do something that makes you happy. ^G ^G ^G ^G ^G ^G ^G ^G- In more laid back days this line would literally sing ^G ^G ^G ^G ^G ^G ^G ^G
On Fri, 21 Oct 2022 at 12:06, Bill W1PA < w1pa@...> wrote: with power plugged in ? --- yes.
If I remove the power and use the battery, the voltage readings seem correct.
In the original post I was measuring from the 817 case to the 13.8 line on the main board and getting 0v (because relative to the DC barrel, they are both 13.8 -- same potential)
b
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I would also check D1085 and T1035- If they have gone open then the DC input wouldn't work. Kindest regards,
Doug Jackson
ph: 0414 986878
On Fri, 21 Oct 2022 at 12:40, Bill W1PA < w1pa@...> wrote: Yeah the fuse next to the three electrolytics was the first thing I checked. It's conductive.
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Hello,
just my experience from this week.
After a repair and a mod (SEL encoder, and Sotabeam filter) everything was working fine. A few days later I tried to power up the radio and I wasn't working anymore - no sign of life. I don't have any internal battery installed so I could check only with external power supply.
I was a little bit puzzled at the problem, because the main bus voltage was not consistent between measurements.
At the end I was able to track the issue down to a broken trace (the one near the power plug which connects the negative of the power plug to the choke filter. So based on where I put the negative lead of my multimeter I could see or not see a voltage. After repairing this track everything went fine and current consumption is normal.
I still don't know the reason for the broken trace. I could see corrosion due to a precedent repair in the area (probably power connector replacement and corrosive flux left in the pcb), which was noticeable even on a picture I took at the radio just before repair and mod, exactly on the broken trace.
Hope that helps,
Il giorno ven 21 ott 2022 alle ore 03:44 Doug Jackson < doug@...> ha scritto: I would also check D1085 and T1035- If they have gone open then the DC input wouldn't work. Kindest regards,
Doug Jackson
ph: 0414 986878
On Fri, 21 Oct 2022 at 12:40, Bill W1PA < w1pa@...> wrote: Yeah the fuse next to the three electrolytics was the first thing I checked. It's conductive.
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Hi
It has been a while since i read about this sort of fault but i do remember someone saying that there is a common mode filter in the power rail at some point and that with a reverse polarity feed and a chassis ground that the negative rail can be taken out. A quick way to check is DC ohms check from the negative lead to the radio chassis.
A long shot but hope it helps
73<DE> Mark
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Thanks, folks. You’ve given me some good things to check. Will report back.
b
Bill ACITO | W1PA
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Today's Update
- I found there is no connection in the power jack from the outside barrel side (negative) to the trace that runs to the common mode choke (negative side). I've soldered a wire to the jack pad so I can power the rig up on external power. With that in place...
- When I plug in external power, as before the rig coms up with all segments and icons black, and if I shine a flash light on the LCD I can see it's trying to display the charge status (CHG TIME RMN and a count down timer.
- If I press the PWR-ON, it tries to boot and shuts off. Removing the power plug and re-inserting takes me back to bullet 1.
If I run on just battery, it tries to boot, and shuts off. Both internal fuses are intact, and I see good battery/line voltage to the display board, and +5v on the display board regulator and the reset chip next to it. Seems like something is dragging it down before it fully boots up. I am assuming the CPU is good because it can display the charge time. Bill
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If the finals are shorted, will the 817 not power up?
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On Sat, Oct 22, 2022 at 09:23 AM, Bill W1PA wrote:
If the finals are shorted, will the 817 not power up?
The finals are straight across the 13.8US (power unswitched), so they might well drag the supply down. If the controller decides the voltage is too low, it will immediately power down. The main power switching (for 5V,6V,9V) is done by Q1104 . I have had this fail. It failed high resistance, (i.e. there was some voltage, just not 12V) From memory, the rig will power off immediately when this fails to switch on - probably because the main 5V will be low. You can probe the switched 12V - TP1084 at the emitter of Q1082 - the big transistor by the 3x13VUS pins down to the PA, and the microphone socket. (block D2 on layout) You can disconnect the the PA drivers with two jumper links on the transmit board next to the PA module. There is a bare wire that connects the 13.8US to the PA module (finals) that you can lift to disconnect the finals. It might be a good idea to do this while you play around getting the rest to run. You should definitely not play around using batteries, best to use a variable supply set to 0.5A current limit. On my version (-ND) there is a fuse for the 13V right before it goes down the 3 pins to the transmit board , (and another fuse for the battery). In the service manual diagrams, I don't see this fuse. (Perhaps that is part of the reason early ones destroy the transistors.)
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I've done some of this.
- I put in an ammeter in line with power, and as the rig powers up, it gets to just over 0.5A draw before it shuts off. As I understand it, the op-amp circuit near the power connector uses the common mode choke as a current sense device and sends a "power off" signal to the CPU to shut things down if it doesn't like what it sees.
- I did unsolder the finals power lead, and removed the two-pin connectors to the drivers, with no help --- thought for sure that would be it.
- I have both fuses on mine, despite what the service manual says -- both check fine.
- I confirmed each of the power rails (5, 6, 9, and 13V) as the rig tries to power up, on the main board and the front display board, but I will look again at the test points you mention.
The service manual is pretty good at describing the RX and TX chains, but there is very little on power-up, reset, and shut-down conditions for the CPU and radio in general -- a common issue with Yaesu service manuals. Wish there more voltages noted in the schematics. b
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On Thu, Oct 27, 2022 at 03:03 AM, Bill W1PA wrote:
I put in an ammeter in line with power, and as the rig powers up, it gets to just over 0.5A draw before it shuts off. As I understand it, the op-amp circuit near the power connector uses the common mode choke as a current sense device and sends a "power off" signal to the CPU to shut things down if it doesn't like what it sees.
This is used on transmit - the limit current would probably be quite high >2A. I would not expect it to trigger at 0.5A even if it was active during RX as this is within the normal operating current range with volume up. You can bridge Q1104 on the top side by connecting 13.8US (3 pins to PA) to TP1084 (emitter of Q1082). Now the radios power will stay on and you can see what the voltages are, and check how much power it is using, and check that voltages (like the main +5) are correctly reaching the front panel. To turn off, the front panel must be seeing an unexpected level on one of the lines that reach it. There is not a lot of smarts on the main board - no processors or other digital devices that return anything to the front panel. i.e. it has to be some static level on one of the lines.
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>> You can bridge Q1104 on the top side by connecting 13.8US (3 pins to PA) to TP1084 (emitter of Q1082).
I did this with a wire and the power-up sequence remains the same -- LCD black, relay click on the filter board, powers off.
I'll add something semi-permanent and see what the voltages look like.
b
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I know this is kinda a long shot here, but Bill W1PA, were you able to solve the problem with your radio? I have one here with the exact same problem as yours.
Plugging in the power results in a black display that's trying to show "CHG TIME RMN" with a count down timer. Orange status LED lit. Pressing power increases current draw from the supply and the radio won't start. Un-plugging power and re-applying it restarts the cycle.
So far I've found fuse F1002 open, but looking at the schematic, that shouldn't cause it to not turn on as it only supplies power to the filer/ PA assembly. A replacement fuse is on the way.
I've also observed the emitter of Q1082 while pressing the power switch. The voltage jumps to 13US, then immediately drops to around 2v. Jumping 13US over to the emitter and forcing it on doesn't do much except make a relay click on the filter board; display still black, CHG TIME RMN with a counter still sorta visible with a flashlight.
I'll check the 5, 6, and 9V rails when I replace the fuse later this week.
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Update - With the main PCB completely removed from the radio chassis and a jumper installed across Q1082, I was able to see good 9v, 6v, and 5v lines. From there, I installed the front panel unit ribbon cable and observed good 5V and 13US on the front panel PCB. I followed 13US back to vreg Q4013 and Q4014 which both had a good 5v on the output.
The front panel LED D4009, TX and Busy hang off the output of Q4013, so if you're seeing this illuminated like I am, you could assume 13US is reaching the front panel.
There are some signals directly from the CPU I need to chase around when I get the time. For now, I'm just going to let the radio finish its charge cycle with the Q1082 jumper removed and no batteries installed. Maybe the CPU is stuck in a weird state that the factory reset couldn't clear.
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Doug Jackson