Need some assistance President Lincoln

[mw0uzo]

I'm repairing a Lincoln for someone. Fixed a load of problems with it but one has cropped up just when I thought I had it in 100% working order, that was not there before I started all the work.

The control buttons channel, band, indicator etc do not respond. The frequency dial is OK. The rig will TX when the mic is keyed. If anyone here has one of these radios, can they experiment with simulating a stuck button to see if they get the sort of problem I am describing?

[PA5COR]

If multiple buttons don't respond, it is not a stuck button, you better look for the connection of the front panel to the PLL board the buttons work for, there will be a connector or something that might have come loose or broken.

[mw0uzo]

If multiple buttons don't respond, it is not a stuck button, you better look for the connection of the front panel to the PLL board the buttons work for, there will be a connector or something that might have come loose or broken.

Thanks for the reply. I have checked for loose wires or open connections to the front panel switch board, but there are none. I will check again tomorrow. I am worried that the CPU is damaged.

The five row/column lines for the keypad measure three at 5V and two at 0V. The pulldown 47k resistor pack is ok. :(

I will unplug the front panel and check the line states tomorrow.

[NQ6U]

Oh, it's about radios. I thought you wanted him to resubmit the Emancipation Proclamation or something.

[mw0uzo]

Oh, it's about radios. I thought you wanted him to resubmit the Emancipation Proclamation or something.

Ha no, but the wiki on that was interesting and showed my complete lack of knowledge about almost everything considered important in recent history...
My wife would probably have bitchslapped me for not knowing immediately what it was. She knows about history and political stuff.

[NQ6U]

Ha no, but the wiki on that was interesting and showed my complete lack of knowledge about almost everything considered important in recent history...

Trust me on this--the majority of us Americans are far more ignorant about the English Civil War than you Welshmen are of ours.

[PA5COR]

I think i might have a lincoln PLL board somewhere, even a working lincoln reset to just 10 meters.
Schematic diagram and all that is somewhere on a USB H.D, too.
It's been years since i tinkered with one....

[mw0uzo]

I think i might have a lincoln PLL board somewhere, even a working lincoln reset to just 10 meters.
Schematic diagram and all that is somewhere on a USB H.D, too.
It's been years since i tinkered with one....

That's excellent news, if I have had a disaster then i'll offer you a good price for the PLL/CPU board. The CPU is a uC-1201A. :)

[PA5COR]

I'll have a look for it, it will be buried in the pile somewhere ;)

[WV6Z]

Pob lwc gyda'r gwaith atgyweirio y President Lincoln.

[PA5COR]

Thank you, we will give it a try :)

[mw0uzo]

Hi PA5COR
Didn't get a chance to get the lincoln on the bench today. Might not be able to tomorrow either. Hopefully sunday evening or monday. I'll post the connector ID and measured voltages on the keypad connector and we can check to see if they match up with your radio. Some measurements with buttons pressed will help too. Thanks again for helping out :)
Dan.

[PA5COR]

Name is Cor ;)
Take your time, i'm not going away soon LOL

[mw0uzo]

Ok got the measurements


J305 CPU/PLL board

1 2 3 4 5 6 7 8 9

Left o o o o o o o o o Right

Gnd F Row Row Row Col Col Swr Swr
Lock 1 2 3 1 2 Cal Cal
Out In
Front

Nothing pressed:
1. 0V 2. 5V 3. 5V 4. 5V 5. 5V 6. 0V 7. 0V 8. 0V 9. 0V

BAND pressed:
1. 0V 2. 5V 3. 4.72V 4. 4.72V 5. 4.94V 6. 4.94V 7. 0.25V 8. 0V 9. 0V

SCAN pressed:
1. 0V 2. 5V 3. 4.72V 4. 4.94V 5. 4.72V 6. 0.25V 7. 4.93V 8. 0V 9. 0V

SPAN pressed:
1. 0V 2. 5V 3. 4.73V 4. 4.94V 5. 4.73V 6. 4.94V 7. 0.25V 8. 0V 9. 0V

INDIC pressed:
1. 0V 2. 5V 3. 4.72V 4. 4.72V 5. 4.93V 6. 0.25V 7. 4.94V 8. 0V 9. 0V

CH UP pressed:
1. 0V 2. 5V 3. 4.94V 4. 4.73V 5. 4.73V 6. 0.25V 7. 4.94V 8. 0V 9. 0V

CH DOWN pressed:
1. 0V 2. 5V 3. 4.94V 4. 4.73V 5. 4.73V 6. 4.94V 7. 0.25V 8. 0V 9. 0V

[PA5COR]

I'll set up the lincoln in the morning and do the testing, and report back.

[PA5COR]

Here's the results
J305
UC 1201A processor/pll

Nothing pressed

0 4.99 4.97 4.97 4.97 0 0 0

Band switch pressed in

0 4.99 4.77 4.77 4.90 4.90 0.18 0 0

Scan switch pressed

0 4.99 4.74 4.90 4.76 0.19 4.90 0 0

Span switch pressed in

0 4.99 4.75 4.90 4.75 4.90 0.20 0 0

span switch ( 2nd time)

0 4.99 4.75 4.90 4.75 4.90 0.20 0 0

Indicator pressed

0 4.99 4.74 4.74 4.90 0.20 4.90 0 0

Channel up pressed

0 4.99 4.90 4.80 4.80 0.15 4.90 0 0

Channel down pressed

0 4.99 4.90 4.80 4.80 4.90 0.15 0 0

Check J 304 as well, i measured some changes there if buttons were pressed.

I have a PDF file of the manual with schematic diagram if need be.

Hope this helps.
This was measured in a working Lincoln, my own one and known to work good.

[mw0uzo]

Ok I'll take a look at J304 too. Looks like the keypad and voltages from the CPU and back are all working fine. Hmmm, must be a fault on the CPU board... but the circuit is very simple and goes straight back to the pulldown resistors and CPU. Is there anything you can do control wise that will stop it reading the buttons?

I'll take a look at the diagram and look for all the inputs. If something is stuck it could hang the keypad detection.

[PA5COR]

First thing would be to to measure J 304 and then you mapped the input from all key's on the front panel.
Lock button could stop the buttons working, but then there is no lock button...
Measure if the CPU/PLL is not out of lock, measure J 304, and if those measurements are good it looks that the CPU is fried.
I also have the technical supplement of the Lincoln, 80+ pages including data about all IC's just have to dig it up.
The only change in my lincoln is the MRF 455 transistor put in for 60 watts out ( separate power supply fed and changed P.A. better filtering too) added Xfilter for sharper narrower reception 10.695 and other 1st recieve transistor ( less noise).introducing BAT 85 low noise Schottky diodes in reception and demodulation AM
Used in the van when solar activety will be higher, resting in the box now


Ok I'll take a look at J304 too. Looks like the keypad and voltages from the CPU and back are all working fine. Hmmm, must be a fault on the CPU board... but the circuit is very simple and goes straight back to the pulldown resistors and CPU. Is there anything you can do control wise that will stop it reading the buttons?

I'll take a look at the diagram and look for all the inputs. If something is stuck it could hang the keypad detection.

[mw0uzo]

Hi Cor
On J304 I have from left to right

1. 0V
2. 5V
3. 0V
4. 5V
5. 0V
6. 5V
7. 0V
8. 5V
9. 0V

I note that J304 controls the display. There is no change to these values if any of the buttons are pressed. If I rotate the frequency dial, these do change as data is clocked into the display chip.

I've double checked all the connections back to the IC - all ok, no sneaky blobs or whiskers. Looks like its the proc :(

PM me with what you want for the spare processor board with postage to the UK and I'll send you the money via paypal and my address.

[PA5COR]

I have the same voltages on my connector.

I have a spare board for free, but there's a catch, i bought it up from our A.T or Offcom they took it from a pirate station working and all, they dod destroy a few coils on that board, but i know the IÇ's are good, as are the rest of the parts.
L 303, 304, 313, 314, 317, 302, 315 missing or broken.
PB 121AD
If you want it, it's free.
No charges for it, i can pop it in the mail this week if you can use it.
The other board i would like to keep for my working lincoln, but with the parts from this one your Lincoln shoulb be working again.

73,
Cor

[mw0uzo]

Hi Cor
Yeah that would be excellent! At least let me send you something to cover postage and a few nice beers :)
Will send you my address via PM.
Thanks so much for helping out :)
Dan.

[N8YX]

Guys,

I may have a leftover CPU board (minus CPU) from an HR-2510. It could be a source of parts if needed.

[PA5COR]

Thanks for the offer John.
But dan is closer to me, and i have the complete board for him, minus a few parts but with all parts he needs in good working order.
I have a few mainboards, and one complete PLL board left for spare parts, i use a Lincoln in the van and it was put back to 20.000 to 29.995.
I keep the good PLL board and can supply parts from the main board if need be just for Islanders for free.

Also front plastic cover,knobs ;) and the like.
Just repay by helping out fellow Hams at the Island.
We are spesjul you now :)

[PA5COR]

Pll board on it's way to the UK, i had to send some BAT 85 Schottky diodes to G6NHU as well, for a friend of him, he already changed his diodes in the FT 847, and was pleasantly surprised by the change it made, so i had to go to the post office anyway.

Lol looks like I'm sending Xmas pressies around..;)

Have fun with it,

73,
Cor

[mw0uzo]

Pll board on it's way to the UK, i had to send some BAT 85 Schottky diodes to G6NHU as well, for a friend of him, he already changed his diodes in the FT 847, and was pleasantly surprised by the change it made, so i had to go to the post office anyway.

Lol looks like I'm sending Xmas pressies around..;)

Have fun with it,

73,
Cor

Brilliant, thank you! :D

Barkeep, a smörgåsbord of wonderful drinks for this fine gentleman.

[mw0uzo]

The board arrived today. Hopefully, I'll get the CPU off and fitted to the other board on Monday. :)

[PA5COR]

All the critical components will work, incluuding the PLL chip etc.
Use the standard esd protection removing them.

[mw0uzo]

Use the standard esd protection removing them.

Yes I will be taking additional measures against static. This may well have been the first time I've been bitten by it :/

[mw0uzo]

Got the replacement CPU off the board. Desolder wick unfortunately did not remove enough solder from the through holes despite my best efforts. Had to use hot air station to get CPU off and quite a lot of heat. I hope I have got it off without damage.

Currently pondering what to do about the original board. Cut old IC off and solder onto stubs? Remove with hot air station? I was planning on sockets, however the pin spacing is narrower than the usual sockets I have.

[mw0uzo]

Ok decided on a plan. Gonna desolder the suspect IC with the hot air station, remove the remaining solder with wick, hoping that the through holes are cleared and solder in the replacement.

[mw0uzo]

Got the orginal IC off, removed excess solder and opened through holes....

[PA5COR]

Could work, though i would just have cut off the IC and soldered the new one on to the small stumps left on the board, less heat in the PCB, less stress on the components on the board, no damage to the pcb traces too, a small crack in the pcb traces is sometimes difficult to find ( freeze spray) , but whatever you feel comfortable with will work in the end ;)

[mw0uzo]

new IC in place, plenty of smt flux...

[mw0uzo]

Doh, called in to help make dinner...!

[mw0uzo]

Passed smoke test, chanel buttons work!!!!!!

[mw0uzo]

Band switch works! YAY!

[mw0uzo]

CPU operation is perfect. All controls and features work :D

Changing that IC was probably the most difficult soldering task I've ever done that worked afterwards.

The frequency dial encoder is a bit iffy, I'll sort that out tomorrow and put it bang on frequency and then it will be perfect.
Thanks very much for your help and the spare CPU, Cor :)
Now where are these drinks ;)

[PA5COR]

Just happy i could help, the most difficult work was done by yourself actually ;)

Just repay the deed with help of another ham member here if you can, i'm not rich, but then if i can help another ham i will, part of whaat i am and what i consider being a ham is all about.
Good to see you get the Lincoln back to work, congrats for that, and that is what makes this hobby great ;)

Got me some 200 meters 2 and 3 mm guy rope for the inverted L with Vectran and a lot of strength, so i'm looking forward to some nice weather to redo the guy lines for permanent set up and put it back up to 77 feet vertical section.( now at 70 feet for the winter storms).

73,
Cor