Chip switch for Lincolns

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lbcomms
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Re: Chip switch for Lincolns

Post by lbcomms »

@Otter The only reason we went for Atmel over PIC was familiarity, not any technical differences. Most of our other MCU work is in Atmel land, so going that route for this project means we are more likely to have components and reusable code handy. We overcome the lack of battery backup using either a battery backed RTC chip on the I2C bus (if it needs to keep the time) or an FRAM chip if it doesn't (unlimited / fast writes like SRAM but no backup power needed).

We'd only need to store data like current and memory frequency values so it'll be FRAM for this one. Update it every time the user changes frequency, it only needs a millisecond or so to save the data if a user turns off after a change.
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Re: Chip switch for Lincolns

Post by Otter »

lbcomms wrote: 01 Oct 2019, 20:29 We'd only need to store data like current and memory frequency values so it'll be FRAM for this one.
That's what I'm using. It's also updated in one of the operation modes if it stops on a scan for more than a certain period of time. The latest boards have a second I2C device - a serial EEPROM - so that user defined bands could be stored, but I stopped my project before writing code to support that one.
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Re: Chip switch for Lincolns

Post by ct3im »

ch25 wrote: 05 Feb 2019, 11:10
lbcomms wrote: 25 Jan 2019, 12:30One minor hiccup, don't have a datasheet for the LCD driver IC (IC502, Sharp LH5008TP)
The same chip like uPD7225.
Chris

Hello , my name is Hugo from Madeira Island , i am a new user , escuse my bad english.
I have a problem with a president lincoln , no frequency on Display , smeter works fine. The LCD IC is the LH5008TP , but now in not easy to find this chip. I read yours post and you said the uPD7225 is same chip. In fact i have in hand one other lincoln with the IC uPD7225 but the PCB layout is different , the “output” pins for the LCD have the same configuration but the pins 1 to 13 to “comunicate” with microcontroller board have different configuration , for exemple , in LH5008TP pin 1 is connected to pin 56 with a resistor , but in uPD7225 pin 1 have no connection , the same occur with other pins.

Now i have two questions.
Did you direct replaced one to other without modifications ?
Second question, is possible replace for the uPD7225 with modifications in pins?
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Re: Chip switch for Lincolns

Post by lbcomms »

A direct replacement is unlikely, but haven't looked at it that closely as we were only communicating with the existing display chip from a replacement micro. It sounds like in your case the display itself is the issue, not the controller. Seen a few dead / partially dead displays but can't ever remember seeing a bad controller IC. Failed electrolytics can also cause some silly symptoms in these.

We've put this and all other projects on hold due to local carona restrictions.
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Re: Chip switch for Lincolns

Post by MrWeetabix »

Welcome back Lbcomms..... been a while 👍
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Otter
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Re: Chip switch for Lincolns

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lbcomms wrote: 09 Sep 2020, 19:30 Failed electrolytics can also cause some silly symptoms in these.
Most of the display faults on President Lincoln type radios are to do with a faulty electrolytic on the dislpay PCB.
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Re: Chip switch for Lincolns

Post by Otter »

ct3im wrote: 08 Sep 2020, 20:46 Did you direct replaced one to other without modifications ?
Second question, is possible replace for the uPD7225 with modifications in pins?
I think (I am not 100% sure) that the main difference between LH5008TP and uPD7225G00 is that on LH5008 pin 6 is VDD and pin7 is VSS and on uPD7225G00 pin6 is VSS and pin7 is VDD.
But before you do anything, replace all three electrolytic capacitors on the display board.
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Re: Chip switch for Lincolns

Post by 14CS06 »

Hello

why not reverse the 2 decks

@+
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Re: Chip switch for Lincolns

Post by df2tb »

ibcomms asked for a Lincoln 1 with a Chipswitch if I remember correctly. Is this still true? I now have here both and I could send it to lbcomms if necessary.

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Re: Chip switch for Lincolns

Post by John555 »

I'd be really interested in one of these for my Lincoln. Two things that have always bugged me are the lack of ability to scan 5k increments and the speed that the scan resumes after dwelling on an active frequency.
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Re: Chip switch for Lincolns

Post by lbcomms »

Never went anywhere, just hard to post new stuff when we've had to abandon most workshop activity and I've been relegated to office duties.

I'll get back to the technical stuff when the gathering and travel restrictions are lifted down here, but this year is not looking too promising...
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Re: Chip switch for Lincolns

Post by Otter »

I emailed you the LH5008 datasheet a couple of hours ago Sue. I forgot whether I did it before.
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Re: Chip switch for Lincolns

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You did send it before around the start of the year, thanks again.
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Re: Chip switch for Lincolns

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Otter wrote: 09 Sep 2020, 20:46
ct3im wrote: 08 Sep 2020, 20:46 Did you direct replaced one to other without modifications ?
Second question, is possible replace for the uPD7225 with modifications in pins?
I think (I am not 100% sure) that the main difference between LH5008TP and uPD7225G00 is that on LH5008 pin 6 is VDD and pin7 is VSS and on uPD7225G00 pin6 is VSS and pin7 is VDD.
But before you do anything, replace all three electrolytic capacitors on the display board.

Hello, i have checked with more atention and result is, the LH5008TP have 52pins and uPD7225 in presidente lincoln have 56 pins , but exist the uPD7225 with 52 pins .
Now i have buyed One piece on ebay (because didnt find in local market) and i am Waiting for him.
I have found the pinouts , for LH5008 and uPD7225 , some “old” Kenwood use the LH5008TP.
Previously i have replaced the electrolitic capacitors but result is same, no Display.
I have two president lincoln , one with no frequency (only s-meter working) , other Display full working , I have disassembled both to compare and do some test , when i assemble again the working module , now frequency not work anymore.
Result , I will wait for “chip” arrive and do some more test and revive the frequency.
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Re: Chip switch for Lincolns

Post by cb4ever104 »

ct3im wrote: 15 Sep 2020, 12:46 I have disassembled both to compare and do some test , when i assemble again the working module , now frequency not work anymore.
I hate when that happens !
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