Helix HX-4700 back on the bench

[Lasonic TRC-920]

In an effort to prepare for the International Boombox Meet in Las Vegas, I have made a list of radio's I will be taking and work that needs to be done to take them.

I'm sure you remember this build "Helix HX-4700 Custom".



In the time that has past since I built this radio, it has hit the streets a few times. One of them being at the Relay For Life event last summer and another time at the beach.

Most of it's time is spent plugged into the wall.

But what I noticed is, the LED system I built was pulling to much off the power supply. Over a short period of time, the radio would start cutting in power and the lighting would dim out.

So, I have been formulating a plan to resolve this issue.

What I came up with is the simplest way to go and that is to set the LED system up on it's own battery supply and let the stereo run on it's 10 D cells.

The issue I faced is that I set up the LED's to run off of 15V (10x 1.5v D cells).

In order to get 15v worth of power, the plan was to use two 9v batteries (18v) and cut the power down to 15v for the LED's. LED's are very power specific. Resistors are used to get the right power and I set all of them up to run on 15v. So without taking it all out and changing the resistor values on all the LED's, this is a cheap way of doing this.

To begin with, I bought a few items to do this job...

Two 9v batteries (these are cheapies for testing, I will be running Duracell's in the finished product)



One voltage regulator IC chip



Two 9v battery connectors



One prototyping breadboard for testing



A bundle of test leads




The voltage regulator IC cuts the input voltage, in this case, 18 volts, down to a pre-set voltage of 15v. You can buy them in almost any voltage setting you need. I watched a youtube video on how this works here

The nice part about this set up is, if the two 9 volt batteries don't last very long, I can simply add a third 9v, upping the input to 27 volts and still get 15 volts out. Hopefully the two 9 volt's will last a long time, but only testing will let me know.

To start with, I wired up the batteries to double the voltage to 18v



Tested the battery voltage...



Next I set up the breadboard with my components to test the setup before soldering it all together



I connected the batteries to the voltage regulator
Left pin Power IN, Center pin GROUND, Right pin Power OUT



And test...



Next was to solder the battery connectors together and add shrink tubing.



I then had to locate the power and ground wire for all the LED lighting from the on/off switch. I added connectors to them so when I remove the back of the radio I can unplug them since the two 9v batteries will be going in the spare tape compartment on the rear case.



These wires come from the re-purposed "Beat Cancel" switch on the front of the radio.



Now to solder the 9v battery wires to the voltage regulator IC (Left In, Center Ground, Right Out)



Add some shrink tubing to prevent shorting...



Wired with the 9 volts...



Now, I simply plug into the LED power leads on the radio...



Press the button AND presto...LIGHTS!



As expected, the IC chip run's hot. So I have ordered a tiny heatsink (3/4" x 3/4") to attach the IC to. Then I will mount it in the box and test it to see how long it takes to eat two 9 volt batteries.

I'm not really worried if it only lasts a few hours. This radio is more of a novelty and less of my "Go To" box. I have plenty of radio's for that. But I think this radio needs to ROCK Las Vegas under the neon lights!

 

[blu_fuz]

Nice little project. At least you had a direction to go in and it looks to be working out.

 

[JustCruisin]

Diggin your little alligator clip clamp for the circuit board.. Very handy tool!

 

[Lasonic TRC-920]

Nice little project. At least you had a direction to go in and it looks to be working out.

Be it a custom bike, car or blaster, when you build something, there is a "Shake Down Period".

Since I built this radio, it seems that I was straight on to the next project and didn't really get a chance to put any miles on it.

Yes, the setup works as I had hoped. Walked out to the garage to throw the switch a few more times (also was getting a beer from the fridge)

The last time in, I pinched the IC chip between my fingers to see how hot it was really getting. It was getting warm, damn near hot. Not sure how hot it would get over the long term, on a hot So Cal day, in the middle of summer!

For the hell of it, I placed the IC on the amplifier heatsink and to my complete amazement, in 1 second it was cool to the touch!

OK, got heat sinks on the way...Might just drill a hole in the amp heatsink and call it a day!

Diggin your little alligator clip clamp for the circuit board.. Very handy tool!

That little clip holder is a life saver when soldering. I only got 2 hands!

 

[jimmyjimmy19702010]

'Helix HX-4700 back on the beach' -'I was thinking, great some outdoor beach pics!! misread the bloody title! Oh well, some pics of your workshop will have to suffice!

 

[SLO]

Thats some good work Chris, Vegas deserves to be graced by this badass Helix!

 

[mancardo]

Dang Chris....I wish I had half the knowledge & experience you have to fix and work on these Boomboxes. :'-(

 

[Lasonic TRC-920]

'Helix HX-4700 back on the beach' -'I was thinking, great some outdoor beach pics!! misread the bloody title! Oh well, some pics of your workshop will have to suffice!

If I can get this working right, I would love to get her out and Rock the streets. Hopefully this will do it

Thats some good work Chris, Vegas deserves to be graced by this badass Helix!

Thanks Steve, so, should I put the white Lasonic Speakers in?

Dang Chris....I wish I had half the knowledge & experience you have to fix and work on these Boomboxes. :'-(

I wish I knew much more, but thank you. Every idea I come up with, I figure out from tinkering and searching the internet or watch a youtube video! I wish I had the knowledge of SuperDuper and Caution. Then I could build some crazy stuff.

 

[Lasonic TRC-920]

Since I am in here working on this radio, there is one more thing I want to address.

If you remember, I installed light cord around the speakers



But this was a closed system, powered by a small box that held two AAA batteries. It had it's own on/off switch. It also was sound activated, which required an internal microphone and an adjustable volume knob.

I stashed this power pack in the spare cassette compartment in the back of the radio.

The real issue with this set up is, it's yet another switch to push. I have to power up the radio, then power up the bluetooth, then power up the LED's, then power up the light cord, then power up the clock.

So, I have pulled the light cord controller out of it's battery case. It contains the microphone, volume wheel, connector to the light cord, on/off switch (which will be left on) and adjustment wheel



The plan is to get another voltage regulator that will step the power down from 15 volts that the LED's are running on, to 3 volts (2x 1.5v AAA batteries) that the light cord runs on and connect it to the power distribution board I made up for the LED lighting system.

Then I want to mount it inside the radio and mill a small slot in the side of the box so I can access the adjustment wheel. I want to hide it so you can't see it, but you can just run your fingers over it to make the adjustment. WHY IS THAT IMPORTANT? The light cord can either be set too ALL ON (volume up 100%) or set to be sound activated. The problem is, as the radio's volume goes up and down, so does the sensitivity. So, if I want that feature to work, it has to be manually adjusted. And I want it to work.

Here are some locations I am thinking about



I have ordered the voltage regulator and it should be here about the same time as the heat sinks, of which this regulator will get one. Then it should be just putting it together and onto the next project for Las Vegas!

I think the Louder Blaster will be going, so I will go through that and make sure it's a go!

 

[oldskool69]

Nice work Chris!

 

[Lasonic TRC-920]

Nice work Chris!

Thank you

I managed to get the light cord routed above the tuner over to a location I want to mount the control board. Not sure any light will come through the tuner glass, but I had extra so WTH.

Just waiting on the heat sinks and 3v voltage regulator.

 

[trippy1313]

How hot did that regulator actually get?

Different application but I use a 12v regulator for those BT modules Joe found, I can run that 8 hours without a heatsink and not get warm at all.

Probably just because of different uses maybe? I supposed the constant change in the draw from the lights might be why?

 

[Lasonic TRC-920]

How hot did that regulator actually get?

Different application but I use a 12v regulator for those BT modules Joe found, I can run that 8 hours without a heatsink and not get warm at all.

Probably just because of different uses maybe? I supposed the constant change in the draw from the lights might be why?

It was getting hot, I held it pinched between my fingers, it wasn't going to burn me, but I want the components in this box to run at a lower temp than that.

 

[goodman]

Very good upgrade!

 

[blu_fuz]

I like the hidden lighted wire module with just the wheel sticking through the chassis to adjust sensitivity.

 

[caution]

Swanky mod Chris! Well executed.

 

[Lasonic TRC-920]

Very good upgrade!

Thank you sir

I like the hidden lighted wire module with just the wheel sticking through the chassis to adjust sensitivity.

Thanks Joe, I have yet to mount the board, will probably do that after I have the heat sinks and know where everything will be mounted. But it was either I turn up the sensitivity all the way and the lights stay on (which I will still have the option of doing) or do away with it all. I recieved the voltage regulator, so I am good to go on this part.

Swanky mod Chris! Well executed.

Thank you Eric

 

[BoomboxLover48]

Joe,

Good project and excellent work!

You mentioned...

"The nice part about this set up is, if the two 9 volt batteries don't last very long, I can simply add a third 9v, upping the input to 27 volts and still get 15 volts out. Hopefully the two 9 volt's will last a long time, but only testing will let me know."

​In this case more heat needs to be dissipated.

I would stay away increasing the input voltage much higher that the output voltage. This will drain the battery faster too. Heat dissipated is part of power used up from the batteries.

I think it is better to add 2 additional 9V in series and connect them in parallel to give 18V input with four 9V and prolong the life. Using 2 rechargeable 9V batteries is better too.

 

[caution]

Yeah, add pairs of 9V batteries in parallel for longer life at the same voltage.

 

[Lasonic TRC-920]

Joe,
Good project and excellent work!
You mentioned...
"The nice part about this set up is, if the two 9 volt batteries don't last very long, I can simply add a third 9v, upping the input to 27 volts and still get 15 volts out. Hopefully the two 9 volt's will last a long time, but only testing will let me know."
​In this case more heat needs to be dissipated.
I would stay away increasing the input voltage much higher that the output voltage. This will drain the battery faster too. Heat dissipated is part of power used up from the batteries.
I think it is better to add 2 additional 9V in series and connect them in parallel to give 18V input with four 9V and prolong the life. Using 2 rechargeable 9V batteries is better too.

Yeah, add pairs of 9V batteries in parallel for longer life at the same voltage.

SEE...this is why I post and YES, that makes TOTAL sense (and since wifey gets 9v batteries free from work WTH )
Still waiting on the heatsinks, they are on a slow boat from China, but since I bought 10 of them for $0.77 with free shipping it's hard to complain! (how the hell do they do that???)
Once I have those, I have one more thing I'm adding to this project and I am done.
This radio uses a small battery powered Bluetooth receiver. The battery lasts between 4-8 hours, depending on the situation. It is recharged with a standard USB cable, so I am going to add a 3v USB plug so I can just charge it off the on board D cells. I already did it to the Wheely. You can see that here.
$1.39 delivered!