Vela Discolite Will Not Power On

Hey guys,

I lucked up and picked up a nice discolite for a fair price. I knew before I purchased it that the owner could not get it to power up. I am in the preliminary tests to begin locating the source of the problem, but would like to ask for pointers from some more experienced members.

The only info I have from the old seller is that the system worked fine until he put in batteries. He states that he put in batteries the system stopped working' and he hasn't been able to get it to power on via batteries or mains. I have tried so far with mains and have verified I am getting no signs of power.

Sellers description. I could not reproduce any movement in the tape motors as he stated. (sorry for his all caps)
" I TRIED 10 BATTERIES AND AFTER A FEW MINUTES SOMETHING WENT LIKE A TRANSFORMER OR RELAY, SWITCH OR SOMETHING. THE FM, LINE IN AND ALL THE LIGHTS DID WORK BEFORE THAT. SO I PUT THE 16V PLUG BACK INTO BACK AND THE FM, DISCO LIGHTS AND LINE IN STOPPED WORKING AND JUST THE CASSETTE FWD AND REWIND WORK?"

I have the system open and I am looking for the problems I have found with systems that haven't powered on in the past. All wires seem to be soldered and the power switch appears to be fine upon first visual inspection. The power switch is however a push button built on the board so I have not found any obvious ways to bypass the switch to eliminate it from the possible issues. I have visually checked the fuse and it appears to be fine. I have played with the voltage selector to see if it was corroded with no luck..

I would really appreciate pointers for my next courses of action. I am assuming I will need to pick up a voltage meter to get more detailed in my trouble shooting process. If so, any recommendations on what to pick up would be appreciated also.

Thanks

Radio in question
[ebay]110627747460[/ebay]

It is in much better cosmetic condition than that pictures lead to believe. It is complete other than the discolite emblem from the grill, which the seller says he has somewhere around the house. But I do not know if he will ever be able to find it, so if someone has one please let me know. Other than the obvious power issue... if I get this difficult to locate part, respray the grill and dust it off, it will be an excellent example of this model.

Hey Reptoid is it possible if you could send me a pic of the power supply? I have an extra one from a 777 that I know works and wondered if they are the same. If so we can make a deal and it's yours. Let me know! Jr.

send a PM to old ramon/monchito--
he has done some great repairs on his and on mine
----------------------------------------

as for that missing emblem---
its so hard to find --that after a few years of looking--
i finally had to MAKE ONE !! :'-(

it looks like a home-made POS -- done by a child -
but still better than nothing-

i will try and get a shot for you

If you have power turning deck motor then you might want to try the function selector switch may be pretty dirty

here is one with my fugazi gold emblems

( its just stick-on gold letters )

Jboogie2384 said:

I have an extra one from a 777 that I know works and wondered if they are the same.

Click to expand...

Good call. I just cracked open a 777 and unfortunately they are different. Other than the general look and shape of the two boxes, they don't appear to hold any major similarities internally.

redbenjoe said:

send a PM to old ramon/monchito--
he has done some great repairs on his and on mine
----------------------------------------

as for that missing emblem---
its so hard to find --that after a few years of looking--

Click to expand...

Thanks Ira, I will see if Ramon has any pointers. I also just wrote the seller to let him know how important that emblem was to me!

baddboybill said:

If you have power turning deck motor then you might want to try the function selector switch may be pretty dirty

Click to expand...

Good call I will double check that again. I let my friend borrow my cleaner, but am getting it back tomorrow. I did put some elbow grease into it with no signs of life. I am unable to reproduce the power turning the deck motor that the seller stated or any signs of power in the box.

redbenjoe said:

here is one with my fugazi gold emblems

Click to expand...

I would never have been able to tell from the photos. I really hope the seller can dig that emblem up for me.

and for the jollies.......

here is a different discolite with my over-the-top
experiment for the speaker trims --
i think all the factory models had black or gold trims
around the speakers --

so - some day - some nut will paint them orange or red

redbenjoe said:

and for the jollies.......

here is a different discolite with my over-the-top
experiment for the speaker trims --
i think all the factory models had black or gold trims
around the speakers --

so - some day - some nut will paint them orange or red

[ Image ]

Click to expand...

Ira, you ARE that nut! Orange 'em up asap!

Or send her over here and I'll do it!


Best of luck repairing her, Reptoid. She's well worth all the effort.



Rock On.

Johnny. You definitely need to pick up a meter if you want to be diagnosing boxes. Without one, you are flying blind and just guessing.

I had 2 for sale here: http://www.boomboxery.com/forum/viewtopic.php?f=5&t=5839

Restocat owns the yellow goldstar now but the more capable triplett meter is still available.

Although highly unusual that batteries alone would cause something like this, one area that could be suspect is the power switch. On many boomboxes, the cassette functions are independant of the FM/Line-in, etc. Those are powered on by the power switch. Although it is soldered in place, with a meter, you should be able to test it to see if it works properly. If you can shoot me a pic of the power switch, I can suggest which pins to test. It can be tested in circuit so it doesn't have to be removed.

Another thing that could've happened is that the batteries could have been installed backwards. If so, it would not be uncommon for the filter capacitors to BLOW UP. Yep, that's right, BLOW UP. So check them for bulging. If they blew and shorted, then it could draw enough current away to prevent normal operation. However, cassette motor might still work, even with low low voltage if there is no load.

Anyhow, those are 2 places to start.

Superduper said:

Johnny. You definitely need to pick up a meter if you want to be diagnosing boxes. Without one, you are flying blind and just guessing.

Click to expand...

You are right. I will contact you to pick up your triplett meter, I knew it was a matter of time before I needed one. I have a background in PC repair where I once had a room of spare parts to swap and diagnostic discs, which isn't the case with radios for obvious reason. Thanks for your insight, I will get those pics up tomorrow and ask your opinion. There is in fact some discoloration on some capacitors.

Board that handles the power input from the mains and battery. The orange goop on the two large caps is what I was describing above.



Power switch casing/body. Left is 'On / Off Sleep' right is 'On / Off'


Power switches on board. Top (blue switch) is 'On / Off' Bottom (red switch) is 'On / Off Sleep'


Close up of switches with better view of traces. Top is 'On / Off' Bottom is 'On / Off Sleep'


Power supply. I removed it yesterday and didn't notice any physical abnormalities.

Yeah its pretty dirty so anything could have overheated

Wow. THAT is one filthy boombox. The first thing I would do Johnny is take that out to the garage and using a shop air compressor, blow the heck out of it.

OK as for the capacitors, that residue you see looks more to me like contact cement. Large capacitors frequently are glued down to prevent their mass/weight from damaging the circuit traces they are soldered to from cracking or separating from the PCB.

As for the power switch, those looks like standard DPDT switches to me. There are 2 poles. In other words, each row of three pins represents one pole, and control one circuit. Sometimes, the two poles are bridged (such as the bottom switch) in an effort to double the current carrying capacity (it would be like 2 wires carrying current instead of 1. The center pin (among the 3) is the common and will be latched onto either the first pin or the last pin depending upon the switch position. So if we arbitrarily assign the switch positions as Position A and Position B, then in one position, the common (center pin) will have continuity with one of the other pin, and in the other position, connectivity with the second pin.

So with boombox disconnected from power, set your meter to the ohms scale (you want low range since you are expecting 3 ohms or less) or continuity, then probe the pin pairs as shown in the picture.

Basically, if position A is reading low ohms, position B should read high or infinity. Toggle the switch to the other position. Then retest. The readings should now be reversed. You can verify by toggling the switch with the probes connected. You should be able to cause the readings to change from high (infinity) to low (almost zero) at will by toggling the switch. If you are not getting the expected readings, then your switch is bad.

On the upper switch you'll need to test both poles separately. The bottom switch has the 2 poles bridged so you only need to test the single pole.

So this test here will help you to either find a bad switch or eliminate it as a potential culprit. Also note that you are looking for very low ohm readings. If you are getting high (anything more than a few ohms really), the contacts are likely burned/pitted and the switch can't be saved.

Thanks for the pointers and illustration Norm! I will check the switch in a couple days when my meter arrives. :super: