radio delay off using 528t

I have installed an aftermarket radio in my car, and when I switch from ACC to START/ON, the radio will reboot, the same goes for my factory radio.

I'm guessing ACC drops out during engine crank. I heard I could use the 528T to prevent this, but am completely lost on how to connect it.

Any suggestions on what colour wires to connect to what?

My radio wiring has a +12v constant (to save settings), GND, and a +12v that is switched.

Look at this logically. The ACC wire of your deck (both factory AND aftermarket) is designed with intent to deal with that fact that it cuts out power during crank as well as when the ignition switch is off.

So with that in mind...there is a problem with both your factory and aftermarket deck...or...you need to look elsewhere. A 528T is just a pulse timer...it can not solve the problem you are having. Now if you want a bandaid you could do this. Use 2 1-3 amp diodes (The acc wire draws almost nothing) and set it up like this..

One diode anode (stripe side) to the crank wire...the other diode anode (stripe side) to the ACC wire. Join the cathode sides (non striped) together to the ACC wire of your deck. What this will do is keep power to the decks ACC wire during the crank cycle.

With that said I still would be curious what else could be causing this. I would suspect you are also encoutering a constant voltage drop or loss on the decks constant wire during crank which would most logically explain this problem.



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I can not explain to you what "nothing" is in a scientific way. What makes matters worse is you won't notice it when you finally have the opportunity to experience it.

Go to Radio Shack and purchase (2) 3 amp diodes and a 470 microfarad 25 or 35 volt capacitor and I will tell you what to do with them tomorrow.

Without knowing what kind of vehicle you have, DO NOT connect the 2 diodes from the ACC to Start wires.

I agree and it was an oversight. You do NOT need any caps for this but we should know the vehicle. Not all vehicles use 12vDC for ACC.

To the OP: if you have any fear using diodes and have not already confirmed you have an amp or so of 12vdc current from you acc wire I can give you a safer diagram using a realy to isolate.

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I can not explain to you what "nothing" is in a scientific way. What makes matters worse is you won't notice it when you finally have the opportunity to experience it.

And...with that said it STILL does not explain why your factory of aftermarket deck losing 12v during crank should require a reset of anything, And that is what I personally would be more interested in figuring out rather then bypassing issues with diodes, caps or relays. There has to be a simple reason for this that can be rectified without band aids.

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I can not explain to you what "nothing" is in a scientific way. What makes matters worse is you won't notice it when you finally have the opportunity to experience it.

I'd suggest 2 diodes similar to above but from IGN and ACC +12V with their lines towards 86 of a relay (85 to GND).

Relay 30 can be straight from the battery (thru a fuse; probably 10A) with 87 to the radio (ACC) power. (But break the original ACC power wire to the radio to prevent this circuit powering other "cranking off" ACC loads. That could be done by removing the radio's ACC fuse if it is a dedicated circuit.)

Why would he need both acc and ign? Ignition should not be losing 12v during crank. The issue he is having is the deck requiring a reset after crank. Granted we are basing all info off assumptions because we do not have voltage readings of ign during crank but can assume the deck is hooked up to the acc wire. Now as well we know some newer vehicles do not even have a "true" acc wire but could be using data/ mulipex heck could even be a low current/votlage - at the ignition harness.

Now it might seem I am over complecating it but the root of the problem is actually elementery. The deck is needing a reset during crank (the OP claims both the factory AND the aftermarket deck have the same issue)...so using the info we are given would you not want to determine what is actually causing both decks to lose memory during crank?

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I can not explain to you what "nothing" is in a scientific way. What makes matters worse is you won't notice it when you finally have the opportunity to experience it.

Well...
ACC loses +12V during cranking.
IGN does not lose +12V during cranking.
Hence logically OR both and you have cranking +12V ride thru.

To OR ACC & crank/STart risks 2 breaks during the transition.


If it's a voltage drop issue, the unit will still reset and then a cap else dc-dc converter will be required.

If it's the loss off ACC power (as it seems to be - ie, it is powered by the ACC supply isn't it?), then 2 diodes solve it. And adding the relay means (1) low power diodes (1N400x etc) and (2) no diode voltage drops with option of a direct clean +12V battery source.


PS - I am assuming the radio is still desired on ACC, hence both ACC & IGN.
If not, just move its power from ACC to IGN.

But this does not adress the problem. If the problem with both the factory deck and the aftermarket deck was they did not like a spike or drop during crank then you could use diodes and/or a relay to help this. But would the factory install a deck that would require a reset everytime you lose acc power during crank? Would an aftermarket design a deck that would require a reset every time the acc wire loses voltage during crank?

Do you see where I am going with this? I can assume like myself you have been doing this for so freaking long you think you have seen it all...but realize there is something new to learn every day. Perhaps I am missing something. How could the ACC wire losing power during crank cause both a factory deck AND an aftermarket deck to require a reset after crank? This is my issue here. I think looking at the ACC wire is not the best first place to start in this situation. Granted many of us could come up with countless ways to retain acc power during crank it still makes no sense.

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I can not explain to you what "nothing" is in a scientific way. What makes matters worse is you won't notice it when you finally have the opportunity to experience it.

..lol I still am not allowed to edit.. Yes I agree we could have just suggested to hook the acc of the deck to ign....but that would still not explain the issue and as well is not really a perfect fix since some people would actually like to listen to the deck without the vehicle running and/or the ignition on.

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I can not explain to you what "nothing" is in a scientific way. What makes matters worse is you won't notice it when you finally have the opportunity to experience it.

I was planning to do it with using only the ACC wire. Parallel the 2 diodes, which I know are overkill for this situation. Connect the positive leg of the capacitor to both the Radio's Red wire and the diodes. Ground the capacitor and connect The Car's ACC wire to the other end of the diodes. This will Keep the radio powered up through the start cycle. I know it will keep the radio on for a while after the key is turned off, but it can all be done without any multi-source wiring.

Yeah it is a bit of overkill but really should not be neccesary IF the only problem is acc dropping out during crank. But again at least I would ask...why the acc wire of the deck losing power during crank would be a problem? Why not a problem every time it loses power such as when you turn the ign switch off even if you never started the vehicle?

Now if the compaint was only after an aftermarket deck install that would be one thing, but unless the OP is not being 100% forthright, it seems he had the same issue with both the factory deck and the aftermarket deck. At that point I am curious if this is truly the case..what is the actual culprit. I would love to have meter readings of the acc, constant and groud during crank so I could actually see what is going on here. I am not so sure using a band aid on the acc wire of the deck will fix this....and even if it did I would still have questions. If it did not fix it I would not be surprised even though I did initially suggest the bandaid I am now not so sure it will work as a fix. This is not a radar detector...it is a factory and aftermarket deck both of which have not just a power and ground, but an ACC wire.

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I can not explain to you what "nothing" is in a scientific way. What makes matters worse is you won't notice it when you finally have the opportunity to experience it.

Ah well, you (IAAI) probably know my dislike for the use of large caps for ride-thru circuits. (Caps to hold relays energised - yes; but not for the heavy power.) Plus 2 diodes and a relay are usually cheaper than the (diode &) cap required, and give infinite hold-up time. Of course I was assuming a cranking drop out... (read on).


quark kent - alas no, this is still another boring case of NOT learning something new. It's merely another case of my misreading of the OP - I thought the dropout (reset) was during cranking, not when switching from ACC to IGN.

Ironically my solution is till valid...
I strongly suspect the common worn switch fault where a break occurs between ACC & IGN.
Two diodes solves that problem. The suggested relay adds the aforementioned benefits.


The OP may want to replace the IGN switch if this is a precursor to switch failure, else be prepared for a workaround.
Whether a reset occurs during cranking (as I first thought) is another issue, but if the same IGN +12V source is chosen for the IGN diode, the behavior will be the same as the OEM intent.
However both the above are up to the OP. The OP may indeed choose to investigate the cause and hence perhaps replace the IGN switch - or whatever other solution is needed.

If the problem is ignition switch related....wouldn't it make more sense that it is the constant feed wire that is cuttng out during crank? If it is the ignition wire cuttng out then that should have no effect on the deck since the deck if wired correctly would not be hooked to the ignition wire. Plus the vehicle would not start very well which would be a bigger issue.

Now if the acc wire is losing power during crank that is normal. Unless you are suggesting it is spiking? I could see that being a problem but would find it odd to have the exact same symptons every time on both a factory and aftermarket deck. You can bench those and see what happens..you give the ACC wire power...it turns on..you remoce the acc wire from power,,it turns off. Now see what happens when it loses power on the constant 12v or ground. It typically needs a reset..correct?

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I can not explain to you what "nothing" is in a scientific way. What makes matters worse is you won't notice it when you finally have the opportunity to experience it.

I totally agree. But I'll leave that for the OP to feed back.
Until the OP says it does not reset when first powered on (to ACC), I won't suggest how an IGN switch can break Const +12V.

I know it seems I am over analyzing and I do not mean to do that or dispute your suggestions. I fully agree there is more info required from the OP. However I thought about all possible scenarios including a data module but it would still not explain how cranking could cause the need of a reset (loss of memory I assume) of both a factory and aftermarket deck due to losing power on the acc wire during crank since that is exactly what an acc wire is supposed to do....lose power during crank.

Hence I question the advice of rigging it to retain power during crank as a possible fix. I think there is more to this aka the OP is leaving out something important that seems unimportant but is the key. Most likely something so simple we are all overlooking it. I was thinking something as simple as there is no pwer at the constant wire...but many decks today will not even power up without power on the constant wire at all times. Meh.

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I can not explain to you what "nothing" is in a scientific way. What makes matters worse is you won't notice it when you finally have the opportunity to experience it.

The OP is ambiguous (maybe I did not misread his OP?)...

sniperess wrote:

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... when I switch from ACC to START/ON, the radio will reboot, the same goes for my factory radio.
I'm guessing ACC drops out during engine crank.

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I'm assuming his statement about switching from ACC to START/ON is correct and the "ACC dropping out during crank" to be an erroneous irrelevance, but that's interpreting START/ON to mean IGN.
However "to START/ON" could mean "switching from ACC to ON/IGN" or when pressing START else keying from IGN to START. (The OP has not posted vehicle info as is required by the12volt's rules.)


I provide a solution that solves both contingencies.
Whether the radio handles cranking is another issue, though IMO equipment should look after itself. EG - my Alpine has a direct battery supply yet (usually) turns off during cranking and then reverts to its last state.

As to whether I recommend a diode/cap or diode+diode to relay depends on what the OP means, and what is desired.
As for other possibilities, I usually don't speculate, I merely provide solutions to solve all and let the OP choose. But that means long replies (and boredom, or confusion, or...).
So in this case. I'm KISSing it and waiting for relevant replies.
If the OP were in a hurry, then they sh/would have supplied better & appropriate info, or already have searched (since this type of problem has been answered countless times...).    


Maybe it is a missing const +12V, but I assume the OP has checked for that. I guess I might have covered that if I was one of the first replies but I came in late and was mainly tackling what I thought was unnecessary cost & complication (caps or timers - noting my reset during cranking misread) and wasn't concerned about basics that should have already been covered else implicit. (After all, the OP had specifically mentioned the 528t.)

I was wondering where he got the idea of using a 528T to solve this. There are some great uses for that unit but someone must have given him the wrong advice so he came here asking how to wire it.

Regarsless he states the deck works on acc but clears in both on/run and crank implying it is losing constant. If he won't respond back we can't ask if he checked that but being he is asking about fixing it with a 528T he probably is not being guided in the right direction and/or does not know how to properly T/S a deck issue.

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I can not explain to you what "nothing" is in a scientific way. What makes matters worse is you won't notice it when you finally have the opportunity to experience it.