New expansion - uPD2824 chassis

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cb4ever104
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Re: New expansion - uPD2824 chassis

Post by cb4ever104 »

Ok. Still waiting for my veroboard. You can't really see much , but I've done the parts removal bit and I used a 34pF in mine to get it close to 10.240(18) at pin 14. Waited 20 mins and tuned L16 for 10.24000.
IMG_20211022_192806_resize_48.jpg
Tomorrow I'll remove L13 and wire and fit the oscillator board.

S.
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Handle "Fortune Hunter" back in "the day"
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Re: New expansion - uPD2824 chassis

Post by cb4ever104 »

Oscillator board in. I'll need to wait for my veroboard before continuing. Saying that , I need to check I have all the parts for the nano pcb.
20211023_181336_copy_979x734.jpg
S.
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30TM060
Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
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Re: New expansion - uPD2824 chassis

Post by lbcomms »

Don't forget the Vin wire (orange in my example) BEFORE you power it up - supplying any unpowered IC with input voltages is generally a bad idea. This is the supply voltage to the oscillator board, we used the 5V output on pin 4 of the Nano for this - it also fed the hot (supply) side of the clarifier pot.
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Re: New expansion - uPD2824 chassis

Post by cb4ever104 »

Thanks Sue. Didn't originally see it as it was a bit hidden. Although I would probably have seen it in the image further down the page.
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Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
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Re: New expansion - uPD2824 chassis

Post by cb4ever104 »

Small update. The Spanish postman just tried to charge me €6 import duty for my £4 veroboard that I bought from the UK. Thanks a lot Brexit ! Anyway . I refused it , so I need to source some more. I'll update it again once I start it.
30TM060
Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
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Re: New expansion - uPD2824 chassis

Post by cb4ever104 »

I'm back. Found a bit of scrap veroboard, so I'm using that.

20211102_181617_copy_979x734.jpg
Keen eyed viewers will have noticed that my resistor array is 1 short. I only had a SIP 9 , and I'm not going to use that last pin anyway , so I'll shunt it to GND with a normal resistor. More to follow..

S.
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Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
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Re: New expansion - uPD2824 chassis

Post by lbcomms »

Just tie the last pin to ground, either with a piece of wire or a standalone 10K resistor. That pin controls the offset used by the old 80's legal UK sets, so it's kind of useless on a radio that doesn't have FM anyway...
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Re: New expansion - uPD2824 chassis

Post by cb4ever104 »

Yeah. I saw that Sue. That's why I don't need it. Thanks
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Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
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Re: New expansion - uPD2824 chassis

Post by cb4ever104 »

Bit more.
20211103_193028_copy_979x734.jpg
20211103_193040_copy_979x734.jpg
lbcomms wrote: 02 Nov 2021, 18:21 Sue
Sue. In your photo you seem to have stuck an additional resistor on the 9V TX D2 line. Any reason for that ?

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Re: New expansion - uPD2824 chassis

Post by lbcomms »

That was because I re-used the 858 veroboard circuit. The 858 has 13.8V on Tx, not 9V, so the original uses a 22K resistor.

The 2824 chassis only gives 9V, so to get the same output from the resistor divider a lower value is needed, 10K or so, not too critical. I paralleled the original 22K with a 15K I had on hand, giving 9K total, close enough to 10 for this application.

I could have just changed the resistor to 10K, but left the original in place so it could be used on other radios in the future, such as the MB8719/34 and NDI40013 PLLs - the added 15K would be easier to remove to restore it for a chassis with 13.V on Tx...
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Re: New expansion - uPD2824 chassis

Post by cb4ever104 »

OK . Thanks Sue . I'll hopefully get most of the work finished over the weekend .
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Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
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Re: New expansion - uPD2824 chassis

Post by cb4ever104 »

lbcomms wrote: 09 Jan 2020, 03:00 Wired up and temporarily in radio. The 6 pin header was then used to connect the programmer and upload the firmware.
Hi Sue . I'm almost finished the component and wiring . Just wanted to ask you a question about loading the firmware . Does the nano get its power directly from the USB connection for this , or do the 12V and GND need to be connected ? The answer is probably in one of the threads , but I couldn't see it .

Thanks
30TM060
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Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
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Re: New expansion - uPD2824 chassis

Post by lbcomms »

It does, but it's best practice to fully power up and interconnected digital circuit before connecting an external data source. A loose connection at either end or dodgy cable on the USB could cook the ATMega chip on the nano when you upload to the Nano's data port. I'd install it in the radio and then program the firmware, making sure the radio is powered up when you do it.
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Re: New expansion - uPD2824 chassis

Post by cb4ever104 »

Hi Sue. Ok. Thanks. That makes sense. I'll update the thread shortly with my results.

S.
30TM060
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Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
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Re: New expansion - uPD2824 chassis

Post by cb4ever104 »

I have a couple more resistors to fit and then I need to go through it and check for shorts etc. Before I do that I'm going to replace a few electrolytics , as I won't have easy access to them once the nano board is fitted.
IMG_20211108_130232_resize_21.jpg
S.
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30TM060
Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
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