HR2510/2830/ Lincoln display problem

[riku]

Hello, after hours of searching internet and tried fix this issue i decided to write here and see if someone could please help.

I have a Very very old 2830. it was working fine until suddenly the lcd freq display stopped working.
I turn power on comes 888888 for a moment then it gone. The s-meter and RF/MOD/SWR indication works.

Things what i have done already.
- Recapped whole cpu board, this radio has fixed alot times, but only this time i have no idea what is wrong.
- recapped lcd module, 3 caps
- replaced faulty smd-diode on 7805 what caused voltage to be 5v instead 5.6v. after changing this the screen segments is alot birghter. (those mod/rf/swr and signal meter)
- measured red wire to screen has 5.0volts
- measured both 7808 has 8volts as suppose
- cleaned all brown from pcb. the litle what was left..
- measured xtal 2mhz, its ok. clean sine wave.
- resolder all connections, and cpu etc.
- measured from cpu to the lcd module there is continuity on circuit.
- Measured continuity from ic502 all pins to the lcd panel itself.
- Measured all pull-down R457-466 resistors they are 10k.
- removed 11m jumper to be sure. radio will be anyway used at 10meter band. as i want replace dx5000 with this radio.
- measured with oscilloscope(storage function) the mpu reset signal is about litle over 200ms when power up this should be ok.
- measured with oscilloscope the cable what goes lcd scr,si,cs,cd and nothing there. its 0volt. i have no idea is there suppose to be serial data?
- touching pin 17 on pll does nothing than noice. (google found someone was able to put that way display working) but that radio haved vco issues while mine vco is OK

radio works fine tx and rx, even scan works. but no frequency on screen. i though the mpu is broken, but every function is working like tx and rx vco etc.. so i have no idea?!?
Im running out of options, just hopeing someone has some tips what i can look next. i have used alot hours on this radio at the past fixing aligning etc.. but now this came when it was finally working D

thanks already for help 73's

[cb4ever104]

Hi riku .

Welcome to the forum . I can't really help you much as I haven't had this fault . To be honest I stopped buying 2830's due to their age and need for recapping . I've had a look through some of my manuals and notes that I have on the Lincoln , but I can't find anything useful related to the display fault you have . Hopefully someone else will be able to help you more .

Cheers.

Sammy

[gi4ohh]

did you ever get display sorted

[Otter]

I have a Very very old 2830.

Most (but not all) 2830s were made in 1988.

- measured with oscilloscope the cable what goes lcd scr,si,cs,cd and nothing there. its 0volt. i have no idea is there suppose to be serial data?

The LCD display is only updated when the display changes. If you put the radio into scan mode you should see activity on these lines. The cd line may not change (I can't remember) because this is the command/data line. You should see activity on this line when you release the microcontroller from reset, while the processor is setting up the display chip, but you will need to use a single trigger (probably).

I know you have replaced the capacitors, and checked the connections, but it really does sound like a capacitor or connection to the microcontroller problem.

If this problem only occured after you have been replacing capacitors, I would check for short circuits where you have soldered too.