DiyMobileAudio.com Car Stereo Forum banner
1 - 20 of 34 Posts

·
Wave Shepherd
Joined
·
2,414 Posts
Discussion Starter · #1 ·
So my radio lost a bit of the magic smoke today, and after taking it apart it looks like a transistor (component # Q704) melted.

Now I need a service manual for the Eclipse CD7200 MkII to figure out what it was, and what it is connected to to troubleshoot further.

Any information about Q704 or a service manual would be greatly appreciated.

...



 

·
Wave Shepherd
Joined
·
2,414 Posts
Discussion Starter · #2 ·
I have a service manual on order from United Radio (800-634-8606), but it will take about two weeks to arrive. If anyone finds information before then, I'd love to see it.

Otherwise, I guess I'm the new go-to guy if you need help troubleshooting your CD7200mkii.
 

·
Registered
Joined
·
556 Posts
Am i looking at it wrong ?
as it looks like a input capacitor on the regulator circuit ?
 

·
Wave Shepherd
Joined
·
2,414 Posts
Discussion Starter · #5 ·


I believe the component Q704 is a PNP-style SOT23-size transistor similar to the one in the above image.

I believe the base is connected to two resistors in parallel (R707 & R705), the emitter is connected to a through-hole that goes to a +12v plane, and the collector feeds the 6v voltage regulator. It seems like the failure was an overcurrent situation between the collector and the emitter, but what caused that I'm unsure.

This is all my best guess without the service manual.
 

·
Registered
Joined
·
165 Posts
Interesting...
 

·
Wave Shepherd
Joined
·
2,414 Posts
Discussion Starter · #7 ·
I believe the component Q704 is a PNP-style SOT23-size transistor...

I believe the base is connected to two resistors in parallel (R707 & R705), the emitter is connected to a through-hole that goes to a +12v plane, and the collector feeds the 6v voltage regulator.[/QUOTE]

Service manual arrived today, and my guess was correct. The transistor feeds the voltage regulator (6v) which feeds the main display via the ribbon cable. Component Q704 is a PNP transistor part number: 2SB10730RL

I hope this helps somebody if they try to search for this information. Also, if you need something else from the CD7200mkII service manual (part number SM-1869 ) I can help with that too.
 

·
Wave Shepherd
Joined
·
2,414 Posts
Discussion Starter · #9 ·
After replacing the transistor with one slightly higher capacity, the radio gave off smoke again today. I broke one of the most important rules by just repairing what broke without also discovering WHY it broke. The transistor was not the problem, there is a potential short or other problem downstream of it that is responsible for the overcurrent situation.

I have limited skill with troubleshooting electronics at this small scale and would appreciate some help if any is available. In particular, I'm not sure the best method to isolate a problem that develops over time or spontaneously.
 

·
Wave Shepherd
Joined
·
2,414 Posts
Discussion Starter · #10 ·
After spending some time in the electrical engineering laboratory at school and working with the teachers there, I now believe the front panel display is drawing more current than it should because I remember there are about three or five pixels in the display that are always stuck on. As described to me, the kind of display used in this radio rapidly turns pixels on and off one at a time in a scanning motion, similar to CRT monitors and televisions. So if multiple pixels are stuck on, that would result in the display consuming much more energy than it was designed for. This might explain one of my other symptoms: the faceplate is very warm to the touch.

The best solution would be to replace the display but I need to speak with United Radio about pricing, and it seems a difficult job to do. So in the meantime, I will be trying again to replace the transistor Q704 with a larger component that can dissipate more heat than was specified from the factory, and use the copper chassis of the radio as a heatsink. My goal is to supply the damaged display with the extra power it needs until either everything works fine, or the display eventually breaks.

The trick is to electrically insulate the transistor from the chassis while also retaining high thermal conductivity. The material Kapton is excellent for this, and there is a pad designed exactly for this purpose.

For anyone following along, the parts I'm purchasing from Digikey are:
2SA1725-ND (transistor)
345-1002-ND (kapton insulating pad)
about $2 worth of parts

More updates next week when parts arrive and repairs resume.
 

·
Registered
Joined
·
2,960 Posts
Subscribed. Love that you don't just toss it in the trash after round 1.
 

·
Wave Shepherd
Joined
·
2,414 Posts
Discussion Starter · #12 · (Edited)
With all the posts I have found about displays not lighting up, I hope by documenting this process I can help at least someone else who is interested in repairing their display on their own. Or, I suppose if this is successful in the end I could help others by repairing their radios for them. I dunno, I just hope this is helpful.



This is the schematic from the service manual. Component Q704 provides 8V to the front panel's LEDs, and also 8V to the 6V voltage regulator, which then provides 6V to the front panel's main display.

Here is the chain of events as best I can put it together:
The main display over time developed dead pixels which drew much more current than normal, causing the transistor Q704 to overheat and fail. When I tried to repair it the first time, I failed to use a heatsink with the replacement transistor and it overheated and failed. Somewhere in the troubleshooting process I applied too much heat to resistor R704 and it failed too.

So now I have replaced the transistor a 2nd time along with the 10k resistor hoping it would be able to cope with the additional current required if I use the copper chassis as a heatsink (the very top edge of photo below shows this):



Unfortunately, the display was still pulling over 2amps of current and the transistor would heat up immediately, plus the 6v voltage regulator is only designed to provide 1 amp max. So I tried isolating the problem further by testing each resistor and capacitor in the chain and discovered it was indeed the display pulling all the excess current. So I cut the trace on the circuit board in the schematic below and then all the components were running cool and the LEDs would light up, but the display itself was of course no longer powered properly and it remained dark.





So, long story short, I need a new display from United Radio. Not the entire front faceplate, just the display labeled as DP1.

Never give up!
 

·
Wave Shepherd
Joined
·
2,414 Posts
Discussion Starter · #13 ·
After bouncing between United Radio and Eclipse on the phone a couple times, I have two options:
-United Radio will repair the faceplate for $175 plus shipping (lol!)
-United Radio will maybe sell me the display piece I want for $76
-Eclipse might maybe possibly have a new faceplate buried in the warehouse, but that will take some time to find if at all

So trying a different approach. Everything I can find hints that the CD3200 faceplate uses the same display unit as the CD7200mkII faceplate does. Actually, they look absolutely identical except for the silkscreen artwork on the outside. Eclipse says they are not compatible and I cannot simply switch the faceplates, but I'm thinking I can buy a CD3200 faceplate off eBay for $29 shipped and then surgically transplant the display into my 7200mkII faceplate. I hope it works ... more updates in a week or two after it arrives.
 

·
Wave Shepherd
Joined
·
2,414 Posts
Discussion Starter · #14 ·
After bouncing between United Radio and Eclipse on the phone a couple times, I have two options:
-United Radio will repair the faceplate for $175 plus shipping (lol!)
-United Radio will maybe sell me the display piece I want for $76
-Eclipse might maybe possibly have a new faceplate buried in the warehouse, but that will take some time to find if at all

So trying a different approach. Everything I can find hints that the CD3200 faceplate uses the same display unit as the CD7200mkII faceplate does. Actually, they look absolutely identical except for the silkscreen artwork on the outside. Eclipse says they are not compatible and I cannot simply switch the faceplates, but I'm thinking I can buy a CD3200 faceplate off eBay for $29 shipped and then surgically transplant the display into my 7200mkII faceplate. I hope it works ... more updates in a week or two after it arrives.
 

·
Banned
Joined
·
2,535 Posts
I have a ton of Eclipse CD7000 to 7200 original boxes with manuals and or stuff in, let me check to see if I have an extra face
 

·
Wave Shepherd
Joined
·
2,414 Posts
Discussion Starter · #16 ·
VICTORY

(please please please last longer than a day like the first two repairs ........)

Everything went exactly as planned. I purchased a spare CD3200 faceplate from eBay and transplanted the vacuum fluorescent display from a spare into the the broken faceplate for my CD7200mkII. It was very tricky getting the displays off of the circuit board without applying too much heat and damaging something, and also without applying too much physical force when trying to remove them. They are made of glass are are very rigid but also very brittle and I broke the broken one when trying to remove it from the 7200 faceplate.


These are the two faceplates I have to work with. On top is my broken CD7200mkII, and on the bottom is the spare CD3200 I bought off eBay. They are identical in all respects except for color, silk-screen graphics, and something related to the display drivers. I could plug the 3200 faceplate into my 7200 radio and everything would function but the display was garbled.


The inside of both faceplates as above. The vacuum display module is absolutely identical from the pinout to the markings to the numbers printed on the inside of the display. It was a perfect fit.

I am absolutely thrilled! The new transistor is installed and heatsink'ing well, the new display is in the faceplate, and the current flowing is only a quarter-amp which is 8x less than what it was before. Mission success.

I really hope this helps somebody, somewhere, somehow.
Never give up, never give in, and you will learn something and win in the end.
 

·
Registered
Joined
·
165 Posts
That is sweet!!! Good job on your troubleshooting. The faceplate boards looks similar.. I wonder what would have happened if you just tried the complete 3200 face on the unit?

I'll keep an eye out for lit up pixels on mine.
 

·
Wave Shepherd
Joined
·
2,414 Posts
Discussion Starter · #18 ·
That is sweet!!! Good job on your troubleshooting. The faceplate boards looks similar.. I wonder what would have happened if you just tried the complete 3200 face on the unit?

I'll keep an eye out for lit up pixels on mine.
I tried that at first, hoping against hope that it would be compatible. All the buttons seemed to work and the buttons also light up just fine. The main display was garbled and not readable (I'm guessing because of some communication problem between the different faceplates, or maybe they were made incompatible by Eclipse on purpose), but at least I knew for certain the pixels on that display were working properly before I started surgery.
 

·
Registered
Joined
·
165 Posts
I tried that at first, hoping against hope that it would be compatible. All the buttons seemed to work and the buttons also light up just fine. The main display was garbled and not readable (I'm guessing because of some communication problem between the different faceplates, or maybe they were made incompatible by Eclipse on purpose), but at least I knew for certain the pixels on that display were working properly before I started surgery.
Yeah, probably different display instructions. Back in the day, I had an Alpine 7894 and gave it to my cousin who also had a 7893. The faceplates were somewhat interchangeable, but some features were screwy. BTW, I hated that unit...
 

·
Registered
Joined
·
1,374 Posts
So my radio lost a bit of the magic smoke today, and after taking it apart it looks like a transistor (component # Q704) melted.

Now I need a service manual for the Eclipse CD7200 MkII to figure out what it was, and what it is connected to to troubleshoot further.

Any information about Q704 or a service manual would be greatly appreciated.

...



Hey man, did you ever get the service manual?
I could use a copy.
Would be happy to toss you some $$. :)
 
1 - 20 of 34 Posts
Top