Can't store tuner channels on the HM-HDS1

For all discussions regarding the JVC HM-HDS1 (40GB hard disk and S-VHS recorder)

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EagleFlyFree
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Joined: Thu Mar 03, 2005 11:46 am
Location: Sweden

Can't store tuner channels on the HM-HDS1

Post by EagleFlyFree »

Hi all,

After replacing the HDD a year and a half ago, my HM-HDS1 has been completely hassle free. But now I need your help once more: Yesterday I discovered that my unit had lost all its channel settings. I can still set channels manually, but as soon as I close the confirmation screen, all presets are reset to CH:00 ID:AAAA. I thought maybe there's a battery that needs to be replaced, but the manuals don't say anything about that. Any suggestions?
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Geert Jan
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Location: The Netherlands

Can;t store channels..

Post by Geert Jan »

Hi there,

Looks like the eeprom that stores the channels and settings is broken..
maybe you've got to replace IC3003 (AT24C08).
It;s an 8K bit EEprom from atmel.. commonly used in several other equipment, and shouldn't be hard to find..

good luck..

Geert Jan Laanstra
EagleFlyFree
Posts: 16
Joined: Thu Mar 03, 2005 11:46 am
Location: Sweden

Post by EagleFlyFree »

Thanks for the advice. I'll check it out.
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andywilks
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Post by andywilks »

The basic operating software re: storing channels is the same as on a whole series of straight video recorders. There have been a number of occasions when I've come across eeprom corruption- and often the channels may still tune in but show as blank in the menu settings. When unplugged however, the settings all disappear and a retune will work ok. Yours sounds different to this.
What Geert Jan says is correct to a point, since you appear to have a non functioning eeprom. This may also be due to a missing power rail to it too..
Many models used the eeprom for some extra space for overflow program code however and you will find that the set may not run at all with a blank eeprom in there...you may have to buy a pre loaded JVC one with the data already in it (or read a known good machines eeprom).
There is a workaround but you need to be good at electronics- fit a blank new eeprom and alter the smd resistor connected to 1 pin on the micro which tells it there is overflow programme code to read- ie it then will run and allow storage of tuner data etc, but certain software routines may have a fault (ie autoclock etc)
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Geert Jan
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Location: The Netherlands

Changing EEprom

Post by Geert Jan »

True.. I agree...

But there's more..

You also could try to make a copy of the content of the old one..
Try to program it in the new one.. ( a programmer is required )
Maybe that will solve it completely....
If you need more help .. tell me..

Geert Jan
EagleFlyFree
Posts: 16
Joined: Thu Mar 03, 2005 11:46 am
Location: Sweden

Post by EagleFlyFree »

Problem is solved! I didn't get around buying a new eeprom as the article ID:s were a bit confusing. I also discovered that though I could tune in channels manually I got no sound, which seemed strange. Reading andywilks reply yesterday reminded me that I hadn't tried just pulling the mains plug and leave it for a while. That turned out to be the very simple solution :-). The sound and all the tuner settings were restored.

Feels a bit silly I didn't try this in the first place... But I really appreciate your advice and all the information. Thank you!
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