vcr jvc hr-j610u

[ivtec]

i have this jvc vcr.that i have to reset clock every time power goes off i have to reset the ckock. can you please tell me where in the chassi is the battery or cap that keep the clock on when the power plug is taken out of the wall so i don't have to adjust the clock every time power goes off. Thanks.

[PCBONEZ]

Re: vcr jvc hr-j610u

Never tinkered with VCR's but I imagine it's a soldered on battery in there somewhere.

Will likely be near time circuit which would have a quartz crystal chip as part of the clock. Those are chips are usually mounted in metal cans about the size of a MOSFET that are shaped/look like a can of Spam (rectangular box with rounded corners) and with two leads.

[ivtec]

Re: vcr jvc hr-j610u

Never tinkered with VCR's but I imagine it's a soldered on battery in there somewhere.

Will likely be near time circuit which would have a quartz crystal chip as part of the clock. Those are chips are usually mounted in metal cans about the size of a MOSFET that are shaped/look like a can of Spam (rectangular box with rounded corners) and with two leads.

thanks alot.

[i4004]

Re: vcr jvc hr-j610u

yeah, should be near the display, if not even on its pcb.
it's a high capacity cap...

[Krankshaft]

Re: vcr jvc hr-j610u

Wow all the crappy VCRs I've had didn't have this feature .

You lose power you reset the date and clock .

[Wizard]

Re: vcr jvc hr-j610u

And have been for years. Not even a 32KHz crystal.

Cheers, Wizard

[PCBONEZ]

Re: vcr jvc hr-j610u

They have to have a clock circuit to have a preset recording function.
That doesn't mean the clock has to have a battery back-up.
It wouldn't be hard to put one in even if it doesn't have one.
Find the power to the clock circuit and stick a nicad in parallel.

[i4004]

Re: vcr jvc hr-j610u

>It wouldn't be hard to put one in even if it doesn't have one.

well, it needs facilities to do so, nicd charger circuit etc.

[Wizard]

Re: vcr jvc hr-j610u

The "clock" is the 60hz from the transformer to set the pace on the linear power supply or a 32KHz crystal or multiples of 32KHz frequency if needed if using switching PSU.

But a battery to hold over the clock and settings, I haven't seen one unless is high end version. So far, not yet.

Cheers, Wizard

[i4004]

Re: vcr jvc hr-j610u

>But a battery to hold over the clock and settings, I haven't seen one unless is high end version. So far, not yet.

sanyo from 1989.(not high end at all) has it.
i'm sure i've seen it on more vcrs, although i didn't pay much attention to recent models as that wasn't the issue they had.
(that clock is used to show blinking 00:00 most of the time anyway..hehe)

also, if the op is asking, i guess it means he had that working, and now it doesn't anymore, just like it happens with that battery/capacitor (slowly losing capacity).
changing it on my old sanyo helped, but it didn't last long.

offcourse, if it never worked, it won't work in the future either...heh

60hz?
i thought only cheap and crappy digital clocks use that.
that's pretty unaccurate time keeping.

vcrs usually have cpus that control everything(ic that does display, remote control, buttons, tuner presets system etc.) , and they need quartz crystal to work.
why would they be using main grid if they have that?

[Wizard]

Re: vcr jvc hr-j610u

Actually accurate. I'm aware of utilites changing freq in 24 hour period but they do even it out to low errors.

In fact, one type of chassis in JVC TVs I worked on often, high end has 60Hz optisolator from hot side to cold side that fed cycles to the microcontroller for what? Time keeping and far more accurate.

Cheers, Wizard

[i4004]

Re: vcr jvc hr-j610u

>Time keeping and far more accurate.

time keeping is more accurate if you do it on 60hz vs. few mhz?
he
hehe...


quartz clock can easilly beat this
http://www.vf.utwente.nl/~ptdeboer/misc/mains.html

though yeah, it's much better than i thought....i guess my clock was crappy chinese shit and/or my mains are too dirty for it...heh...

[i4004]

Re: vcr jvc hr-j610u

just checked my vcr; panasonic from 2003 and it has clock backup.
nothing hi-end about it, vhs hifi model that wasn't too expensive...
offcourse being hifi it's not the bottom of the barrel.

[ivtec]

Re: vcr jvc hr-j610u

Thanks guys for your help i'm not very good at vcr repair for one you need paciece of a monk, the other i have no touch for it special when it comes to the mecanism, all i needed was a location Part# in the chassis. i don't know if this jvc vcr ever had the memorie, but i owned a few vcrs like Panasonic,Sony,magnavox,rca my other present vcr and a few others and all when i unplug the wall the clock stays on, so wouls assume that this one wounn't be diferente,any way don't make a big deaL of it.thanks in advance.and A Happy New Year.