stereo loses settings when startup

Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set
stations, it remembers fine going from on to off to access to off. But!
When I start i, the starter seems to drop the "voltage threshold"(at least
that's what I visualize) such that all memory settings are lost.
Ideas, please? Thank you, s

"sdlomi2" > wrote in message
...
> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set
> stations, it remembers fine going from on to off to access to off. But!
> When I start i, the starter seems to drop the "voltage threshold"(at least
> that's what I visualize) such that all memory settings are lost.
> Ideas, please? Thank you, s
>
>
>

Maybe a small 12V battery or large capacitor that's hooked up with a diode
between it and the car battery so voltage to the stereo won't drop when the
car battery voltage drops significantly.

-Bruce

Although it is possible, most aftermarket stereos are quite that sensitive.
My first bet would be on a bad or marginal ground connection for the radio.

Run a separate ground to the battery and a fused positive lead to the
battery and if that eliminates the problem. I have had a variety or
1950-1967 vehicles and failed ground connections from alternator/generator
to block to chassis to dash can be problematic.

Good luck.
Don

"sdlomi2" > wrote in message
...
> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set
> stations, it remembers fine going from on to off to access to off. But!
> When I start i, the starter seems to drop the "voltage threshold"(at least
> that's what I visualize) such that all memory settings are lost.
> Ideas, please? Thank you, s
>
>
>

"Bruce Chang" > wrote in message
. com...
>
> "sdlomi2" > wrote in message
> ...
> > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set
> > stations, it remembers fine going from on to off to access to off. But!
> > When I start i, the starter seems to drop the "voltage threshold"(at
least
> > that's what I visualize) such that all memory settings are lost.
> > Ideas, please? Thank you, s
> >
> >
> >
>
> Maybe a small 12V battery or large capacitor that's hooked up with a diode
> between it and the car battery so voltage to the stereo won't drop when
the
> car battery voltage drops significantly.
>
> -Bruce
>
>
Bruce, thanks. I like these ideas, and prefer the capacitor idea. But,
I need specifics; I understand the theory & agree with you on both. But my
background is ME instead of EE, so I need someone to do a 'practical design'
so I can assemble the components. More help, please? Sorry to ask so
much, but I'll admit where my knowledge ends! s

"sdlomi2" > wrote in message
...
>
> "Bruce Chang" > wrote in message
> . com...
>>
>> "sdlomi2" > wrote in message
>> ...
>> > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set
>> > stations, it remembers fine going from on to off to access to off.
>> > But!
>> > When I start i, the starter seems to drop the "voltage threshold"(at
> least
>> > that's what I visualize) such that all memory settings are lost.
>> > Ideas, please? Thank you, s
>> >
>> >
>> >
>>
>> Maybe a small 12V battery or large capacitor that's hooked up with a
>> diode
>> between it and the car battery so voltage to the stereo won't drop when
> the
>> car battery voltage drops significantly.
>>
>> -Bruce
>>
>>
> Bruce, thanks. I like these ideas, and prefer the capacitor idea.
> But,
> I need specifics; I understand the theory & agree with you on both. But
> my
> background is ME instead of EE, so I need someone to do a 'practical
> design'
> so I can assemble the components. More help, please? Sorry to ask so
> much, but I'll admit where my knowledge ends! s
>
>

I would imagine you could use an IN4001 diode and wire that from a constant
12V to the positive terminal of the capacitor which is connected to the
constant power lead of your radio. The negative terminal of the capacitor
should be connected to the ground of the radio. Everything else should
remain the same.

How big a capacitor? That's a good question. Let me think outquiet.

Energy stored in a Capacitor = 1/2 C V*2 Joules

1 Joule is 1 watt for 1 second.

Your radio will draw 50mA at 12.6 while the engine is off. That's equal to
..63W and multiply for 5 seconds of cranking (I know, I'm doing a lot of
assuming that things remain constant.

Based on those figures, you'd need a 39000uF capacitor or bigger. (if I did
my calculations right). It's been a long time since college.

-Bruce

"Bruce Chang" > wrote in message
. com...
>
> "sdlomi2" > wrote in message
> ...
>>
>> "Bruce Chang" > wrote in message
>> . com...
>>>
>>> "sdlomi2" > wrote in message
>>> ...
>>> > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I
>>> > set
>>> > stations, it remembers fine going from on to off to access to off.
>>> > But!
>>> > When I start i, the starter seems to drop the "voltage threshold"(at
>> least
>>> > that's what I visualize) such that all memory settings are lost.
>>> > Ideas, please? Thank you, s
>>> >
>>> >
>>> >
>>>
>>> Maybe a small 12V battery or large capacitor that's hooked up with a
>>> diode
>>> between it and the car battery so voltage to the stereo won't drop when
>> the
>>> car battery voltage drops significantly.
>>>
>>> -Bruce
>>>
>>>
>> Bruce, thanks. I like these ideas, and prefer the capacitor idea.
>> But,
>> I need specifics; I understand the theory & agree with you on both. But
>> my
>> background is ME instead of EE, so I need someone to do a 'practical
>> design'
>> so I can assemble the components. More help, please? Sorry to ask so
>> much, but I'll admit where my knowledge ends! s
>>
>>
>
> I would imagine you could use an IN4001 diode and wire that from a
> constant 12V to the positive terminal of the capacitor which is connected
> to the constant power lead of your radio. The negative terminal of the
> capacitor should be connected to the ground of the radio. Everything else
> should remain the same.
>
> How big a capacitor? That's a good question. Let me think outquiet.
>
> Energy stored in a Capacitor = 1/2 C V*2 Joules
>
> 1 Joule is 1 watt for 1 second.
>
> Your radio will draw 50mA at 12.6 while the engine is off. That's equal
> to .63W and multiply for 5 seconds of cranking (I know, I'm doing a lot of
> assuming that things remain constant.
>
> Based on those figures, you'd need a 39000uF capacitor or bigger. (if I
> did my calculations right). It's been a long time since college.
>
> -Bruce
>

I'd be cautious of using a 1N4001 diode for this purpose as it has a current
capacity of 1 amp. Unlike some older units, most newer head units draw full
power from the "constant" lead and use the "switched" lead only as a signal
for the head unit to power on/off - backwards of what one might tend to
think. Other head units used the [typically orange] "constant" wire only for
memory retention. The reason they have started using the "contant" wire
instead of the "switched" wire for power is so that head units with
logic-controlled cassette mechanisms, CD players, and motorized faceplates
can load/eject with the ignition off.

Roger

On Mon, 31 Jan 2005 16:32:41 -0500, "sdlomi2" >
wrote:

> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set
>stations, it remembers fine going from on to off to access to off. But!
>When I start i, the starter seems to drop the "voltage threshold"(at least
>that's what I visualize) such that all memory settings are lost.
> Ideas, please? Thank you, s
>
>

Have you checked the retained power line to make sure that it still
has power when the starter is engaged? If it doesn't have power even
for a couple seconds your radio will loose its settings.

Steve B.

In article > ,
Bruce Chang > wrote:
>
>"sdlomi2" > wrote in message
...
>> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set
>> stations, it remembers fine going from on to off to access to off. But!
>> When I start i, the starter seems to drop the "voltage threshold"(at least
>> that's what I visualize) such that all memory settings are lost.
>> Ideas, please? Thank you, s
>>
>>
>>
>
>Maybe a small 12V battery or large capacitor that's hooked up with a diode
>between it and the car battery so voltage to the stereo won't drop when the
>car battery voltage drops significantly.
>

You need two diodes. One diode prevents the car from trying to charge the
small batteries, and the second to keep the small batteries from trying to
help crank the starter. The large capacitor will cause a voltage
spike, just after the motor starts, so a choke coil will be needed to
protect the sound unit.

Here, in the Great White North (How's it goin', eh?), we would advise you that
your battery is seriously short of cold cranking amperage and that you
should buy the biggest battery that will fit in the tray. However, being
designed for old-tech batteries, you should accept anything that covers half
of your '55 studebaker's battery tray. While cold weather starting may be
the least of your worries, a larger battery is the simplest (if not the
cheapest) solution to your problem.

"Richard Bell" > wrote in message
...


> Here, in the Great White North (How's it goin', eh?), we would advise you
> that
> your battery is seriously short of cold cranking amperage and that you
> should buy the biggest battery that will fit in the tray. However, being
> designed for old-tech batteries, you should accept anything that covers
> half
> of your '55 studebaker's battery tray. While cold weather starting may be
> the least of your worries, a larger battery is the simplest (if not the
> cheapest) solution to your problem.
>
I couldn't agree more, all those other fixes are just going to hide the
symptom and not repair the problem which is either a bad battery, a bad
connection or bad wiring.
Bob

"Steve B." wrote:
>
> On Mon, 31 Jan 2005 16:32:41 -0500, "sdlomi2" >
> wrote:
>
> > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set
> >stations, it remembers fine going from on to off to access to off. But!
> >When I start i, the starter seems to drop the "voltage threshold"(at least
> >that's what I visualize) such that all memory settings are lost.
> > Ideas, please? Thank you, s
> >
> >
>
> Have you checked the retained power line to make sure that it still
> has power when the starter is engaged? If it doesn't have power even
> for a couple seconds your radio will loose its settings.
>
> Steve B.

This is what I was thinking. Maintaining memory settings were no that
big an issue back in '55, so a hard line to the battery might be hard to
come by.

Its best to run a dedicated wire from the battery (+), with an in-line
fuse near the battery to the radio 'battery' input. If the radio is
supposedly already connected to a hot point, the radio dropping out
might be a symptom of a dirty, weak or loose connection, or a charging
system problem.

--
Paul Hovnanian
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RAM disk is *not* an installation procedure.