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Old 18th Jun 2022, 12:57 pm   #1
1100 man
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Default 3v22 clock. 12 or 24hr?

I've been rebuilding two of these clock modules using new LED's. Please see my other thread for further information.

The first one was from my 3v16 and displayed a 12 hr clock with a dot to indicate AM or PM.

Trying to be clever with the second one (from a 3v22), I omitted to fit 5 of the seven LED's for the first digit - after all it would only ever display a '1' or be blank, so only two LED's would ever be used.

I rather smugly powered it up when I'd finished, only to find this one was a 24hr clock!

They would seem to be the same clock module and have the same JVC part number on the back, so my question is why is one 12hr and the other 24hr?

Can this perhaps be set by a combination of button presses? Sometimes on clock modules there is a board link to select 12 or 24, but I can't see anything on either of these. The manual doesn't give the circuit of this module.

So it would be great if somebody could shed some light on this slight puzzle!

All the best
Nick
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Old 18th Jun 2022, 6:38 pm   #2
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Default Re: 3v22 clock. 12 or 24hr?

Looking at the instructions for the JVC 3320 clock setting there only appears to be 24 hour mode.

Peter
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Old 18th Jun 2022, 10:40 pm   #3
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Default Re: 3v22 clock. 12 or 24hr?

Thanks Peter. So it looks like the 3v22 one would be 24hr anyway then. I wonder if it's the 3v16 one that's the odd one out?

Looking at the clock chip fitted, it's an SC3044 made by NPC in a 40pin DIL package. I can find pictures of it on the internet but no datasheet. There is a SC3044B which is totally different - that's an 8 pin surface mount thing.

It would be interesting to find out which pin does the 12/24hr selection - assuming there is one.

Also, I wonder if the 3v16 user instructions mention whether it's a 12 hr clock?

Cheers
Nick
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Old 18th Jun 2022, 10:57 pm   #4
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Default Re: 3v22 clock. 12 or 24hr?

I thought all JVC (3V series are Ferguson clones of JVC) machines in GB had 24 hour clocks. In fact as I remember all VHS sold in GB had 24 hour clocks except some Hitachi models. Machines sold in the US had 12 hour clocks. They could be changed over (either way) and usually it was a matter of moving diodes. But finding out which ones is difficult. Getting hold of a US service manual for a similar machine may reveal the differences.
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Old 19th Jun 2022, 5:13 am   #5
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Default Re: 3v22 clock. 12 or 24hr?

I have not repaired a" Clonker Box" for probably 30 + years,but I think I possibly remember only the 3V00 having a 12Hr Clock , the 3V22 was 24 Hr.
The 3V16, would have been a 8916 to us RR/DER lads, and I cant remember us having that particular model, perhaps it was 12 Hr as well
Back in the day, 1979/80, us Engineers were put on a two week VCR servicing course, and I don't recall being told any thing about a option for changing the 12/24 hour clock settings, it was a comprehensive course, even the clock 50/60 Hz setting was mentioned and discussed.
Therefore I think a 12/24 option, if it existed would have also been discussed on the course.
Up in my loft somewhere I still have my course training notes, I will try and find them and have a look.
Ken, G6HZG.
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Old 19th Jun 2022, 7:11 am   #6
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Default Re: 3v22 clock. 12 or 24hr?

I've noticed that US/Canadian-market, Australian-market and some Middle Eastern-market machines use 12hr clocks whereas UK/European-market etc machines use 24hr clocks. I don't know why this is a thing. Some Sanyo machines have a jumper that you move across to change between 12 and 24hr modes.

Fivos
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Old 19th Jun 2022, 12:20 pm   #7
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Default Re: 3v22 clock. 12 or 24hr?

There's an article in Television magazine (Dec 82 p98) on this and other VCR clock chips. Earthing pin 33 changes from 24 to 12 hour display.
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Old 19th Jun 2022, 2:04 pm   #8
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Default Re: 3v22 clock. 12 or 24hr?

Brilliant! Many thanks, Bill.

Having scrutinised both boards for jumpers or links that might change from 12 to 24hr, I completely missed the 15K resistor soldered on the print side of the board in full view! It's not as though it wasn't obvious - I think it was so obvious that I assumed it should be there!

It's possible, back in the mists of time, that might have had something to do with me. I originally sourced this machine for a friend's elderly relative back in the late 1980's who needed something very simple to use. I might have modified it for 12hr clock to make it less confusing...

Sure enough, removing this resistor that grounds pin 33, puts the clock into 24hr mode.

Mystery solved I think!

Thanks for the input from everyone on this,
Cheers
Nick
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Old 19th Jun 2022, 4:59 pm   #9
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Default Re: 3v22 clock. 12 or 24hr?

Quote:
Originally Posted by its ur aerial View Post
The 3V16, would have been a 8916 to us RR/DER lads
8904 actually and I’m almost certain it was 24hr also.

John.
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Old 21st Jun 2022, 12:20 am   #10
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Default Re: 3v22 clock. 12 or 24hr?

Quote:
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Quote:
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The 3V16, would have been a 8916 to us RR/DER lads
8904 actually and I’m almost certain it was 24hr also.

John.
That's right John, 8900, 8904 and 8922, were the models I remember too.
And the 8904 and 8922 definitely came new out the box with 24Hr clocks.
So was a 3V16 badged up to TTR as a 8922 then, and was that one with the two tracking controls and plug in RCU?
I always assumed a 8922 was a 3V22

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Old 21st Jun 2022, 7:52 am   #11
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Default Re: 3v22 clock. 12 or 24hr?

8922 was a 3V22 and 3V00 an 8902, unlike the Ferguson versions there were no cosmetic differences between the two TTR models.

John.
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Old 21st Jun 2022, 1:15 pm   #12
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Default Re: 3v22 clock. 12 or 24hr?

Ken, do you remember the 8928? These were fun, PAL/NTSC 4.43/MESECAM stopgap model brought in to cope with demand, no Ferguson equivalent. Customers used to flick the slide switch from PAL to NTSC even though it was blanked off with a piece of plastic. The effect was a non existent servo fault.

John.
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Old 21st Jun 2022, 7:14 pm   #13
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Default Re: 3v22 clock. 12 or 24hr?

No sorry John, no recollection off a 8928 I obviously remember the 8923/24 8941/42 etc.
I left RR in 1989 and started working for my self, at that point RR were starting to rent Mr A Sugars tawdry effort at producing a VCR .
I assume the 8928 was after I left.
Although we did rent some odderties, we once had a delivery of Nat Pan VCR`s, that were destined for rental at the "Foreign and Commonwealth office," which I understand is Government parlance for MI6 they were collected by two men in brown warehouse coats driving an immaculate Astra van...ohh... eer.
Happy days.
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Old 21st Jun 2022, 11:48 pm   #14
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Default Re: 3v22 clock. 12 or 24hr?

Quote:
Originally Posted by jayceebee View Post
Ken, do you remember the 8928? These were fun, PAL/NTSC 4.43/MESECAM stopgap model brought in to cope with demand, no Ferguson equivalent. Customers used to flick the slide switch from PAL to NTSC even though it was blanked off with a piece of plastic. The effect was a non existent servo fault.

John.
Never heard of an 8928. But I do recall a JVC with that spec. I think it was HR-3330TR. They were grey imports with a BG tuner and RF converter. Did the 8928 have a BG tuner as well?
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Old 23rd Jun 2022, 1:29 pm   #15
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Default Re: 3v22 clock. 12 or 24hr?

It did have a multiband tuner but never tested one with a B/G signal, modulator output was system I of course. The TR in the model number, could it mean Thorn Rentals I wonder?

John.
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Old 23rd Jun 2022, 1:56 pm   #16
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Default Re: 3v22 clock. 12 or 24hr?

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Originally Posted by jayceebee View Post
It did have a multiband tuner but never tested one with a B/G signal, modulator output was system I of course. The TR in the model number, could it mean Thorn Rentals I wonder?

John.
If it had a system I modulator it is highly likely that front end was also system I unless modulator had been tweaked from system G which is, of course, possible -
System I with standard all-band tuner would have been a requirement in Ireland
J
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Old 23rd Jun 2022, 6:43 pm   #17
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Default Re: 3v22 clock. 12 or 24hr?

Quote:
Originally Posted by jayceebee View Post
It did have a multiband tuner but never tested one with a B/G signal, modulator output was system I of course. The TR in the model number, could it mean Thorn Rentals I wonder?
Unlikely. It would be a model for southeastern Europe and the middle east, given the PAL/MESECAM/NTSC4.43 playback features it supposedly sports. The service manual might explain the exact destination market for which the suffix TR stands.
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Old 23rd Jun 2022, 8:16 pm   #18
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Default Re: 3v22 clock. 12 or 24hr?

Quote:
Originally Posted by jayceebee View Post
Ken, do you remember the 8928? These were fun, PAL/NTSC 4.43/MESECAM stopgap model brought in to cope with demand, no Ferguson equivalent. Customers used to flick the slide switch from PAL to NTSC even though it was blanked off with a piece of plastic. The effect was a non existent servo fault.

John.
Yes that's the HR-3330TR. I have one in fully working order. It does play NTSC tapes fairly well.

Fivos
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