alpine 7802 unable to set clock
Printed From: the12volt.comForum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=132125
Printed Date: May 10, 2025 at 3:44 PM
Topic: alpine 7802 unable to set clock
Posted By: onurmarc
Subject: alpine 7802 unable to set clock
Date Posted: September 02, 2012 at 9:58 PM
Howdy, to all you expert Audiophiles,
I recently bought a used car with an Alpine 7802 old school HU, and no matter what I try, I can't get the clock to start flashing, so I can set it.
I have searched the internet for the manual or some literature about this radio and the only info I can find is from guys in forums like this, so that's why I'm asking for help with this here.
I private messaged someone here also, so hopefully either he or you guys can help me.
The writing is pretty worn off of the controls and through pictures that I've found on the internet, (one that's below), I've pretty much been able to figure out how everything works, and for how old it is, it seems to be pretty good quality. But even though I can get the clock to display, either while the tuner is playing or not, I can't find the right key to hold to make it flash, so it can be set. Then, even if I do find the right key to get it to set, then which keys do I use to set the min. and hours?
Any help in this, I'm sure, is a simple matter, will be appreciated. I feel so dumb, not being able to figure this out myself. Even though, an owner's manual would be nice to have with this unit.
P.S. I found some other units that are pretty close to this unit, but I can't find any info or manuals on them either. (pics below)
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I recently bought a used car with an Alpine 7802 old school HU, and no matter what I try, I can't get the clock to start flashing, so I can set it.
I have searched the internet for the manual or some literature about this radio and the only info I can find is from guys in forums like this, so that's why I'm asking for help with this here.
I private messaged someone here also, so hopefully either he or you guys can help me.
The writing is pretty worn off of the controls and through pictures that I've found on the internet, (one that's below), I've pretty much been able to figure out how everything works, and for how old it is, it seems to be pretty good quality. But even though I can get the clock to display, either while the tuner is playing or not, I can't find the right key to hold to make it flash, so it can be set. Then, even if I do find the right key to get it to set, then which keys do I use to set the min. and hours?
Any help in this, I'm sure, is a simple matter, will be appreciated. I feel so dumb, not being able to figure this out myself. Even though, an owner's manual would be nice to have with this unit.
P.S. I found some other units that are pretty close to this unit, but I can't find any info or manuals on them either. (pics below)
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Replies:
Posted By: i am an idiot
Date Posted: September 03, 2012 at 1:01 AM
Posted By: DYohn
Date Posted: September 03, 2012 at 11:27 AM
i am an idiot wrote:
If you can not find any info on setting the clock. Following are failsafe instructions to set the clock on any radio out there, OEM or aftermarket.
Disconnect battery for a few minutes, reconnect battery and notice if the deck has 12:00 or 1:00, it will be one or the other. Now set a timer or alarm clock for 11:50 or 12:50, disconnect the battery and reconnect it at 12:00 or 1:00.
Why yes, that should work! 
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Posted By: onurmarc
Date Posted: September 03, 2012 at 12:06 PM
Posted By: oldspark
Date Posted: September 04, 2012 at 3:57 PM
Posted By: i am an idiot
Date Posted: September 04, 2012 at 8:51 PM
Posted By: oldspark
Date Posted: September 05, 2012 at 2:39 AM
Posted By: tommy...
Date Posted: September 05, 2012 at 9:29 AM
Posted By: oldspark
Date Posted: September 06, 2012 at 2:46 AM
Posted By: tommy...
Date Posted: September 06, 2012 at 8:26 AM
oldspark wrote:
I'm an Idiot!!!
The CDM9821 was my previous (with the blown faceplate thanks to a bad engine to body ground).
My newie is a CDE-121E.
Thanks Tommy. Sorry - my bad! (And not how I expected to be "wrong".)
I was a little worried...
We have the CDE-121 Here. This Unit Does have a Clock. The CDE-121E is not a Model # here. Your old unit had the capability to Switch for Over-the-Pond stations. Is that what the "E" represents...?
**Im looking at Alpine Austrailia, now... I posted the Manual. I am sure you have a copy and have perused it... Just to Add it...
https://www.alpine.com.au/files/OwnersManuals/cde_121e.pdf
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M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!
Posted By: oldspark
Date Posted: September 07, 2012 at 4:10 AM
Posted By: tommy...
Date Posted: September 07, 2012 at 10:05 AM
Posted By: oldspark
Date Posted: October 29, 2012 at 8:38 PM
Sorry for this re-awakening, but not wanting to start a new Post... (me? Never!) - especially if it's obvious, well-known, trivial, or posted elsewhere.
In summary:
Why?
Some units may have a high standby current when BOTH constant and switched +12V are connected.
For example, for the Alpine CDE-121E, connect either constant +12V (yellow) or switched +12V (red) to +12V and their loading is negligible.
BUT, connect both to +12V and their combined loading jumps to ~80mA (or ~120mA with USB memory inserted).
That sort of drain is too much for many users. (Me included, but I only found out about that increased drain AFTER buying a new battery!)
Noting that I'm in the habit of turning off my Alpine/HU manually, and that I want it available anytime - even when I've lost my keys!
My solution was to run the switched +12V thru a relay (#30, #87). Coil #85 to GND...
Switched +12V thru a diode to coil #86, and...
HU Remote Turn On (eg, blue-white on Alpine) thru a diode to coil #86. (The RTO latches the relay on.)
The above means that once switched +12V is on (whether ACC or IGN) the HU can be turned on.
Once the HU is turned on, it stays on until manually turned off, or the supply voltage drops sufficiently (eg, to below 11V) - irrespective of ACC or IGN status.
Later I'll add a switch to bypass the need for keys (for ACC or IGN) - eg, short #30 to #86 (via diode?).
I might even add a switch to break the Remote Turn On to #86 in case I want the ignition key to also turn the HU off.
And yes, I should have a low-voltage cutoff in case I forget to turn the HU off, but that's only happened a few times with my previous Alpine which had a blown faceplate and hence no display (just the panel back-lights that were almost invisible in situ during daylight).
Oh well, what was intended as a simple FYI or warning now includes my full-blown blurb. How strange!
Meanwhile I can't help but notice how technology has defeated me again!
Long ago I scrapped the "IGN or battery" selector for my HU power instead favoring direct to battery.
And now I'm back to at least using a relay, plus a switch if I want to turn it on anytime.
Just you wait Tech - I'll get rid of the switch. One day...
Sorry again for the re-awakening of this thread.
Sorry too onurmarc for the hijack, but I thought with this thread being concluded etc...
And anyone, please paraphrase or use the above in another the12volt thread if suitable.
In summary:
- I've always wired my audio straight to the battery
- This can no longer be done on modern HUs (maybe).
Why?
Some units may have a high standby current when BOTH constant and switched +12V are connected.
For example, for the Alpine CDE-121E, connect either constant +12V (yellow) or switched +12V (red) to +12V and their loading is negligible.
BUT, connect both to +12V and their combined loading jumps to ~80mA (or ~120mA with USB memory inserted).
That sort of drain is too much for many users. (Me included, but I only found out about that increased drain AFTER buying a new battery!)
Noting that I'm in the habit of turning off my Alpine/HU manually, and that I want it available anytime - even when I've lost my keys!
My solution was to run the switched +12V thru a relay (#30, #87). Coil #85 to GND...
Switched +12V thru a diode to coil #86, and...
HU Remote Turn On (eg, blue-white on Alpine) thru a diode to coil #86. (The RTO latches the relay on.)
The above means that once switched +12V is on (whether ACC or IGN) the HU can be turned on.
Once the HU is turned on, it stays on until manually turned off, or the supply voltage drops sufficiently (eg, to below 11V) - irrespective of ACC or IGN status.
Later I'll add a switch to bypass the need for keys (for ACC or IGN) - eg, short #30 to #86 (via diode?).
I might even add a switch to break the Remote Turn On to #86 in case I want the ignition key to also turn the HU off.
And yes, I should have a low-voltage cutoff in case I forget to turn the HU off, but that's only happened a few times with my previous Alpine which had a blown faceplate and hence no display (just the panel back-lights that were almost invisible in situ during daylight).
Oh well, what was intended as a simple FYI or warning now includes my full-blown blurb. How strange!
Meanwhile I can't help but notice how technology has defeated me again!
Long ago I scrapped the "IGN or battery" selector for my HU power instead favoring direct to battery.
And now I'm back to at least using a relay, plus a switch if I want to turn it on anytime.
Just you wait Tech - I'll get rid of the switch. One day...
Sorry again for the re-awakening of this thread.
Sorry too onurmarc for the hijack, but I thought with this thread being concluded etc...
And anyone, please paraphrase or use the above in another the12volt thread if suitable.
Posted By: tommy...
Date Posted: October 30, 2012 at 4:47 PM
Posted By: oldspark
Date Posted: October 30, 2012 at 5:31 PM
Hey hang on Tommy - at least I stuck to Alpine. Your hijack is totally unrelated & should be a new thread!
Oh - I get it - in case I want another battery to power mine, or onurmarc a battery to power his clock. Very clever Tommy.
Alas I know little about lithium batteries other than their explosive introduction, and that the LiPo's and rare earth magnets have revolutionised model aeroplanes etc - no more chopping off fingers trying to start miniature diesel engines. (And now that have fan-driven jets as well.)
From what I understand, LiPos are providing "hundreds of Amps" for model plane motors, or that's what one enthusiast was telling me. That may have been somewhat exaggerated, but I take it that they can provide high current and - I presume - with little damage.
I know normal rechargeable lithiums can last ages - far more cycles than the nickel-based rechargeables.
Whether those 2 characteristics combine is a different issue. Maybe modellers don't mind replacing batteries after a dozen flights? (Which would be on par with some UPS batteries - only rated for a handful of full-discharge cycles.)
That's where IMO some data mining is required (read: googling - but only finding the good info LOL).
I'd look in to how long those batteries have been around and lasted.
Two main observations:
- Have they invented a new measurement - "Lithium Amp-Hours"?
- They seem keen to show the flat lithium discharge voltage curve against the lead-acid, but they are using a lithium with much larger Amp-Hour rating. Why? (Did I miss their definition of Lithium-AH?)
Of course the good thing about the voltage discharge slope of the lead-acid is that it's an easy method to estimate remaining %age of capacity. How do you do the same for Lithium?
And as to needing a flat discharge voltage - who cares? Few people run points ignition these days, and anyone with CDI certainly doesn't care, nor would most modern electronic ignitions.
So what if the engine cranks faster?
And AFAIK, a Li battery cannot directly replace a car battery - the charger (alternator) must suit.
Oh - I get it - in case I want another battery to power mine, or onurmarc a battery to power his clock. Very clever Tommy
.
Alas I know little about lithium batteries other than their explosive introduction, and that the LiPo's and rare earth magnets have revolutionised model aeroplanes etc - no more chopping off fingers trying to start miniature diesel engines. (And now that have fan-driven jets as well.)
From what I understand, LiPos are providing "hundreds of Amps" for model plane motors, or that's what one enthusiast was telling me. That may have been somewhat exaggerated, but I take it that they can provide high current and - I presume - with little damage.
I know normal rechargeable lithiums can last ages - far more cycles than the nickel-based rechargeables.
Whether those 2 characteristics combine is a different issue. Maybe modellers don't mind replacing batteries after a dozen flights? (Which would be on par with some UPS batteries - only rated for a handful of full-discharge cycles.)
That's where IMO some data mining is required (read: googling - but only finding the good info LOL).
I'd look in to how long those batteries have been around and lasted.
Two main observations:
- Have they invented a new measurement - "Lithium Amp-Hours"?
- They seem keen to show the flat lithium discharge voltage curve against the lead-acid, but they are using a lithium with much larger Amp-Hour rating. Why? (Did I miss their definition of Lithium-AH?)
Of course the good thing about the voltage discharge slope of the lead-acid is that it's an easy method to estimate remaining %age of capacity. How do you do the same for Lithium?
And as to needing a flat discharge voltage - who cares? Few people run points ignition these days, and anyone with CDI certainly doesn't care, nor would most modern electronic ignitions.
So what if the engine cranks faster?
And AFAIK, a Li battery cannot directly replace a car battery - the charger (alternator) must suit.
Posted By: tommy...
Date Posted: October 31, 2012 at 9:48 AM