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.

I have the ebay aftermarket battery,works fine:

Hi!

Here is a question that I think I know the answer to but here goes - I've a '817ND bought several years back as a 'shack in the box' for use in a small 'domestic' shack. It has never been used "man pack portable" it is fitted with the standard NiMH battery pack just in case..but in practice it was powered almost 100% of the time via an external PSU -? I did cycle the cells from 'fully charged' on a regular basis. This has all been fine and the little box has served me well however the original battery now does not charge to the 'normal' full charge voltage and doesn't hold a charge for long. ?? I have concluded the battery pack has come to end of its useful service life and needs to be replaced.
Since I never use the rig "backpacking" '/p' I think the replacement standard pack is not really worth the outlay - I have the power pole adapter fitted so I can use an external SLAB, or AA Ni-cads or even standard AA cells if I do wnat the '/P' option Are there any known 'gotchas' to this approach ?

73 John G8EWG

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

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.)

In an attempt to clean drawers I have this stuff for sale:

- Yaesu YF-122S original filter (SSB). Like new, w/box. 120€
- New Inrad 500hz filter boards (no filter) for DIY'ers. Easy way is soldering
a 526-8693-010 Collins filter which are available on ebay or similar sites
at various prices, or you can build your own. 2 units, 30€ each.

Items are located in Spain, I'd prefer domestic or EU but will ship anywhere at
actual shipping costs.

Will listen sensible offers.

TIA


--
An expert is a person who has made all the mistakes that can be made in a very narrow field.
--- Niels Bohr

To get the broken tip of the power connector out of the socket I did this trick successfully:
1. Cut a 1" piece of Gorilla tape or gaffer's tape.
2. Roll it into a cylinder approx the same diameter as the barrel plug, with the adhesive side of the tape facing out.
3. Insert the rolled up piece of tape into the socket, making sure the socket pin goes inside the roll of tape. Push it in as far as it will go.
4. Pull it out. The broken plug tip should be stuck to the tape. This might take a few tries.

It is inevitable that this fragile tiny plug will break in your FT-817 power socket. The tape will get it out.

I installed the N0WL Powerpole adapter on the FT-817 after this. Not a permanent mod, and it reliably converts the FT-817 to Powerpole, ruggedly attached to the ground screw.

Alexander N1PRW

Farren,
I have been successful by adding a little solder to the exposed part of the connector and then soldering a wire to that.? Then you can pull the whole thing out.? I bought these a while back and they are great.?
--
Al Skierkiewicz
WB9UVJ

Very small watchmaker's screwdriver also works.? I managed to lever mine out like that.? Now have PowerPole adapter fitted!

Mike
G8NSZ

--
Steve, G4VRR.

¿ªÔÆÌåÓý

I bought one of these.

Takes the strain off the plug

¿ªÔÆÌåÓý

I recently purchased a used 817 and I just discovered that the yellow plastic tip from a power plug is stuck down at the bottom of the power socket on the radio.? Any suggestions for how to remove that from the socket?

Worst case, is that power socket available so I can replace it?? Got a DigiKey part number??

Thanks!

-Farren / KB0AZJ

If the finals are shorted, will the 817 not power up?

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