Help making a Volvo radio test system (Update)

Post by **scot850** » 16 Sep 2022, 16:06

I watched Robert's as usual helpful video below:

https://www.bing.com/videos/search?q=fi ... &FORM=VIRE

This got me thinking about making up a simple test system to:

1) Power the radio up
2) Allow the radio to stay on long enough to remove the dreaded 'OFF' if CODE set wrongly (I have one unit that does not accept it's code but I think it had a stuck button)
3) To check the functionality of the unit like CD-input and eject functions (especially 3-CD head units), cassette input eject as well as being able check all the bulbs are working.

Maybe down the line I might add a simple speaker function that would allow checking sound output as well as testing the amplifiers.

I have pig-tails from the 2 larger radio connectors.

I have difficulty following Robert's directions as to which wires to connect for power to get the units functional.

I plan to power this from a trickle charger with 2/4A output capability to save buying a 12V power supply. I also have a couple of 2/6A battery charger is more power is needed.

I want to make sure the system is safe for me to use and also safe for any head units attached to it.

This is a winter project but any design guidance is appreciated!!

Many thanks,

Neil.

Post by **BEJinFbk** » 16 Sep 2022, 22:27

You have two power sources and
a ground to connect to run a radio.

Constant (Battery):
There are actually two leads that share this load.
They provide constant power for amplification
and to keep the clock running. They both tie
together further up the harness:
Pin A4 - Green/Brown
Pin A12 - Green/Brown

Switched (Ignition):
This provides power when the ignition
switch is operated and "wakes up" the HU:
Pin A13 - Yellow/Violet

Ground:
Like the main constant power feed,
this also uses two wires to cary load:
Pin A6 - Black
Pin A14 - Black

I would recommend a dedicated power supply.
Small better chargers, especially smarter maintenance
chargers aren't designed to carry live loads like an HU.
You could also run directly off of a battery easily enough.

No matter what you decide on, be sure to add fuses
to both of your power source connections. If you aren't
connecting speakers and just want to power units up,
a 3 amp fuse for constant and another for the switched
lead should provide adequate protection.

Post by **scot850** » 17 Sep 2022, 02:15

I was planning something similar but not separate fuses for the inputs. This is a much better solution and now I know which wires to power. I will look at a direct power supply. Come to think of it I have tried the trickle power supply before and nothing. Same with my jump-pack. Only my dedicated older style battery charger works for this situation.

I will look into a cheap supply or a spare battery. Would any of these from Amazon work? What type of output do I need? 5A, 10A or higher? I could them use it possibly for testing other car electrical parts.

https://www.amazon.ca/NICE-POWER-Variab ... pons&psc=1

https://www.amazon.ca/Converter-Adjusta ... pons&psc=1

https://www.amazon.ca/Pyramid-Universal ... 94&sr=8-29

https://www.amazon.ca/Adjustable-Switch ... th=1&psc=1

Neil.

Post by **BEJinFbk** » 17 Sep 2022, 14:24

Any of those would work, but some may
be overly complex for what you've described.
If you're interested in a plain-jane, basic unit,
here are a couple of other options with fewer
possible points of failure:

Astron is an industry standard that's built like a tank.
I've seen these operate in constant service for decades:
https://www.amazon.ca/Astron-RS12A-REGU ... 63&sr=1-29

Here's a knock off that's much less expensive:
https://www.amazon.com/TekPower-TP1863- ... 06&sr=8-43

I'd be wary of Pyramid, but to be fair,
I've never used a TekPower supply.

Post by **abscate** » 17 Sep 2022, 14:49

A small tractor battery from princess auto would be cheaper and let you do that power window job too.

About $30

Post by **scot850** » 17 Sep 2022, 14:54

Thanks BJ again.

For the number of times I'm likely to use this in reality, the unit is likely to outlive me!!

The reason I had thought about the variable output was some parts are lower than 12V. So that would allow this to be used for more than just the radio head unit checking I suppose. I did not add that into the requirements lisiting........Oops!

I like the cheaper option for the simplicity, and it looks similar to the 3rd unit in my list. Strangely while similar it is also cheaper on Amazon.ca which is the largest rip off supplier up North. This is one of the few occasions that the pricing seems affordable.

Thanks again,

Neil.

Post by **scot850** » 17 Sep 2022, 15:00

Abscate, like your thinking and did think about that option. However, you need to maintain a battery which has a limited lifespan.

As for the window plan, I am building 2 long wires with clamps for the window and will use the owner's car battery for power but only after disconnecting the car from the battery fully!

That will save me a further $30!

I have been thinking of doing this before for testing/jumping components where wiring issues may be an issue. I am putting an in-line fuse holder that is good to 30A but on 12AWG wire. I will max this out at 10A and see how it goes.

Appreciate the guidance as always!

Neil.

Post by **scot850** » 18 Sep 2022, 10:28

BJ, I have copied and printed off your recommendations.

I am going to look at building this over the next few weeks, but can I ask for some further clarifications on the wiring.

You say there is 2 power requirements and they need separate fuses. If this is a test rig only, why do you need the power lines separate? When you switch on the power supply it would be similar to the key in the car being switched on but there would not be a constant power for the back-up functions anyway. I am putting in in-line auto fuse holders so I can always use larger fuses if needed later if I want to add speakers. The power supplies only have a single output, so the wires would have to be linked. If the wires need to have the wake up separate, then should I add a switch in that line to simulate the ignition?

I am thinking I have possibly a spare pair of speakers that I could connect up to test for sound. Maybe not full stereo as I don't plan to add the small dash tweeters or rear speakers just a pair of door speakers. If I do this how much more power would I need for that.

2nd Question. I also have amplifiers from time to time to test. I have the extra wiring harnesses for those. Any idea how much power I would need for those?

You have awakened a monster!!

Thanks,

Neil.

Post by **volvolugnut** » 18 Sep 2022, 12:24

abscate wrote: ↑17 Sep 2022, 14:49 A small tractor battery from princess auto would be cheaper and let you do that power window job too.

About $30

OR motorcycle/lawn mower battery.

volvolugnut

Post by **scot850** » 18 Sep 2022, 13:18

Again, I did think about the battery route, but then a battery has to be maintained. Also I mentioned having the variable voltage is nice if you want to test those electrical components that are 5V. Also nice to current limit with variable current output. I will 'ponder' this a bit more taking the inputs into account.

I will still add the in-line fuse holders for circuit protection.

Thanks for the input. Always appreciate people taking time to do that!

Neil.