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Fixing a dead Intellivision

transformer power unregulated

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#1 eobard OFFLINE  

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Posted Mon Mar 16, 2015 10:45 PM

A few years back I found an original Intellivision console in a antique shop for only $10 so I bought it. Got it home and it wouldn't power. I cracked it open and found that the transformer was shot. Long story short I tinkered with other transformers to no luck and then shelved it. Well today I took a run at it again and I've made headway. The transformer has been replaced and now the power board outputs are mostly in spec. The 5v, 12v and -2v register fine with my multimeter but the unregulated 16v reads as 33v when tested with my meter. Is this acceptable when the power plug going to the main board is disconnected and the only load is the multimeter? I don't want to hook the power circuit up to the main board and blow it. I know unregulated lines give a wide range of reading depending on the load connected. Is the 16v line 16v when the system is running or just the base output with the cable not connected to anything but a meter?

 

Btw: Nice forum



#2 eobard OFFLINE  

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Posted Tue Mar 17, 2015 9:51 AM

30+ view and no response? Can anyone tell me what voltage they get from their power board's output for the middle pin going between the power board and the main board without the cable connected to the main board please?



#3 thegoldenband OFFLINE  

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Posted Tue Mar 17, 2015 10:56 AM

30+ view and no response?


Unfortunately only a handful of people here are qualified to answer your question, so 30 views doesn't mean much yet. :) Also, fixing broken Intellivisions is a perennially tough topic on this board, inasmuch as many of us have at least one dead console that blackscreens with no idea how to fix it, and no one has really put together a step-by-step, A-to-Z guide.

That said, your question is technically precise (i.e. not "my Intellivision is broken, how do I fix it?") and limited in scope, so I'm sure you'll get an answer before long. It's only been 12 hours since you posted -- but a blink of an eye!

#4 7800fan OFFLINE  

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Posted Tue Mar 17, 2015 11:15 AM

Starting with the obvious: check the cart slot.  I've seen black screen when Intellivision doesn't have good connection with the cart.  Clean, clean, and clean them some more.  Intellivision has a weird setup and it actually does refuse to work if it can't get good connection with the cart. Not like other consoles that displays scrambled screen, funny sound, or crashing while playing,



#5 eobard OFFLINE  

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Posted Tue Mar 17, 2015 12:26 PM

Unfortunately only a handful of people here are qualified to answer your question, so 30 views doesn't mean much yet. :) Also, fixing broken Intellivisions is a perennially tough topic on this board, inasmuch as many of us have at least one dead console that blackscreens with no idea how to fix it, and no one has really put together a step-by-step, A-to-Z guide.

That said, your question is technically precise (i.e. not "my Intellivision is broken, how do I fix it?") and limited in scope, so I'm sure you'll get an answer before long. It's only been 12 hours since you posted -- but a blink of an eye!

Yeah I know it seem a bit pushy and I do apologize for that. Unrelated to the technical issue I'm under a time restraint. My wife's out of town for a bit and I'd like to get this wrapped up and put away before she returns in 3 days so I don't have to face "Why the @#$% is all this crap laying around the living room!?!?!?!!" so I'm hoping someone has an answer for me soon. ;) Even if the answer isn't what I'm hoping for at least then I can put it away without it chewing in the back of my mind about wether I was close to getting it working or not.

 

Starting with the obvious: check the cart slot.  I've seen black screen when Intellivision doesn't have good connection with the cart.  Clean, clean, and clean them some more.  Intellivision has a weird setup and it actually does refuse to work if it can't get good connection with the cart. Not like other consoles that displays scrambled screen, funny sound, or crashing while playing,

This is not related to my issue. I already know what was wrong with the system, the transformer was blown. I've since replaced it with a pair of transformers and I think the output from the power board is good but I'm not willing to just assume it is and then blow out the mainboard if I'm wrong. All I need to confirm my system is in spec is for someone with a working intelivision (original, not II or the sears unit) to crack open their system, unplug the cable going from the voltage regulator board to the main board, then power up the unit and take a volt meter reading between pins #3 (+16v unregulated) and pin #4 (ground). If someone can do that for me and confirm they get an unloaded voltage reading of ~30v then I should be safe to plug in my main board to the power board and then see if there are any other issues down the line. If you follow this link http://www.intvfunho...q/intv_faq7.php and scroll down to section 7.4 you see the layout for both the connector going from the transformer to the voltage regulator board (first image) and from the voltage regulator board to the system board (second image). I just need to know if that 16v is when running the system or if that is an unloaded measurement. That article and any of the other ones I've found online don't specify. If that's a 16v unloaded requirement then I'll most likely blow something on the main board if I hook it up like that. If someone else can confirm that their reading are around 30v unloaded then I feel safe enough presuming that my system is in range to now power up the whole thing.

 

Hopefully I've made things clear enough with my explanation.


Edited by eobard, Tue Mar 17, 2015 12:28 PM.


#6 chas10e OFFLINE  

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Posted Tue Mar 17, 2015 1:52 PM

scrolling down to 7.4 I  get the readings in http://www.intvfunhouse.com/faq/intv_faq7.php 

 

taking the voltages as described I get 21VDC from the far pin on 2 pin connector to center pin on ribbon (says I should have 16V)

 

I got mine @ a thrift for $25 then spent another 10 for a power supply on ebay

 

I would assume it's under load saying to take the measurements off the ribbon cable

 

with ribbon unplugged I get 25.5VDC (had to stick a teeny-tiny piece of wire in there)



#7 eobard OFFLINE  

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Posted Tue Mar 17, 2015 2:25 PM

Beautiful! 25.5v is a lot closer to 33v. I think I'm going to gamble on it and see what I get.

 

btw: I like the link thread here. I used it to get a copy of the official service manual and in the manual it says "Meter should read at least 16v". So it would seem even the official repair manual is vague...



#8 eobard OFFLINE  

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Posted Tue Mar 17, 2015 3:05 PM

S-U-C-C-E-S-S-that's the way you spell success!!!! (sort of)

 

I plugged in the cable to see what I'd get for readings and got 28v with the console fully powered but no game. So I hooked it up to my modern tv's coax and..... nothing. I took a chance that it was the age difference between 1080p LCD digital tech and the intellivision and I hooked it up to an old 19" crt. First power on with a cartridge I got a blank screen for ~3 seconds, then solid green for ~3 secs, then blank again, then solid purple which stayed. I powered off and tried without the cartridge just to see if I got the same green/blank/purple cycle and got a black screen only. Put the cartridge back in and fired it up

 

 

HELLO ASTROSMASH!!!!!!

 

It works but it smells like it's trying to cook something. I'm not sure it the voltages are a bit too high on that one line or if it's just burning off X number of years of dust and pet hair. I think I'm going to consider this a victory for now and see what I can do about getting a more in-sync transformer before I use it for any amount of time.

 

Can anyone tell me what the "blank-bright green-blank-purple" means? Is it in any way diagnostically significant?



#9 freewheel OFFLINE  

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Posted Tue Mar 17, 2015 3:50 PM

My gut tells me that something ain't quite right. INTV consoles either work - or don't, at least in my experience. It's not common to get random colored screens like that. If it's a one-time thing then it's probably just a bad cart connection (even though those usually result in nothing), but if it happens more, combined with a burning smell...

 

It's hard to describe a smell on a forum, but my nose is quite sensitive to the difference between dust vaporizing and electronics frying. Is the smell instantaneous, or only noticeable after a long period of the system being on? An Intellivision can be a bloody hot bastard (it's one of the earliest systems to use a heat sink) but it still takes some time to get there. Frying electronics can start to smell pretty quickly.



#10 HunterZero OFFLINE  

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Posted Tue Mar 17, 2015 6:17 PM

Your unreg voltage sounds off.

Did you test the AC voltages from the transformer connector with the power supply board disconnected?

If these are too high your voltage regulators on the power board will run hot and might fry.

Edited by HunterZero, Tue Mar 17, 2015 6:19 PM.


#11 HunterZero OFFLINE  

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Posted Tue Mar 17, 2015 7:18 PM

From INTV Funhouse (http://intvfunhouse....q/intv_faq7.php):

                                                   _____
                        Yellow Lead --+   ------| |     | 
                          Blue Lead --+   ------| |     | 
                  Green/Yellow Lead --+   ------| |     | 
                         Green Lead --+   ------| |     | 
                         Green Lead --+   ------|_|_____| 
                        Yellow Lead to Blue Lead - 18 VAC 
                Green/Yellow lead to any Green - 9.25 VAC 
                      Green Lead to Green Lead - 18.5 VAC 

In particular, check the voltage across the yellow to blue leads.


Edited by HunterZero, Tue Mar 17, 2015 7:21 PM.


#12 eobard OFFLINE  

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Posted Tue Mar 17, 2015 8:31 PM

My gut tells me that something ain't quite right. INTV consoles either work - or don't, at least in my experience. It's not common to get random colored screens like that. If it's a one-time thing then it's probably just a bad cart connection (even though those usually result in nothing), but if it happens more, combined with a burning smell...

 

It's hard to describe a smell on a forum, but my nose is quite sensitive to the difference between dust vaporizing and electronics frying. Is the smell instantaneous, or only noticeable after a long period of the system being on? An Intellivision can be a bloody hot bastard (it's one of the earliest systems to use a heat sink) but it still takes some time to get there. Frying electronics can start to smell pretty quickly.

I think the GREEN BLANK PURPLE bit was a cartrige contact issue. Not 100% sure about the smell either way.

 

Your unreg voltage sounds off.

Did you test the AC voltages from the transformer connector with the power supply board disconnected?

If these are too high your voltage regulators on the power board will run hot and might fry.

The two transformers I used as a replacement have one primary and two secondaries that can be bridged to make a single with Center Tap. They are the same brand and model and are rated 10V2A each secondary or 20V1A when bridged together. When I tested them unloaded they read 12V/24V instead of 10V/20V but that is unregulated. When connected to the board I get inbetween those two, so It's not perfect but not way out of their spec. I know 18v and 18.5vCT are what the official requirements are but I don't think 20v and 20vCT are too far off. Heck the transformer that was in it when I got the unit was rated way different. Here's what was stamped on the shield in the way it was stamped:

 

G-G/Y-G

15.5v 12.9VA

B-Y 14.5V 7.25VA

 

Which reads to me as 14.5v on the 18V line and 15.5v on the 18.5v (which would split to 7.75v on the CT).

 

That's way below spec and yet (I assume) it ran for the previous owner for a while at least.


Edited by eobard, Tue Mar 17, 2015 8:37 PM.


#13 HunterZero OFFLINE  

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Posted Wed Mar 18, 2015 12:14 AM

Bear in mind that the measured no load secondary voltage is not going to be the same as the loaded secondary voltage. Usually, the no load secondary voltage is higher, as it is in this case. The transformer will give the rated voltage if the specified rated secondary current is being drawn.

 

VA is not "Volts AC", it's the volt-amp secondary rating of the transformer.

 

The service manual gives the rating of the transformers as:

 

B-Y: 15.5V, with 0.275A DC load being drawn from the 2200uF power capacitor.

G-GY-G: 16.0V, with 1A DC load being drawn from the 10000uF power capacitor.

 

It's entirely reasonable that for a transformer with these ratings, unloaded you get B-Y 18V and G-G 18.5V (9.25V G-GY center tap) secondary voltages.

 

I am pretty sure that your 20V/10V transformer setup will eventually cook the voltage regulators and possibly logic board components, such as the transistors that power the CPU, since that's where the "+16V" unreg goes. You could check the voltages at pin 1 and 2 of the CP1610 CPU (should be around 5.6V), but that would require disassembly of the logic board shielding, which is not fun.

 

The +16V unreg power supply output pin should measure about 23V-24V with no load.

 

I recommend that you find a replacement transformer from a donor parts Intellivision.

 

- J


Edited by HunterZero, Wed Mar 18, 2015 12:18 AM.


#14 eobard OFFLINE  

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Posted Wed Mar 18, 2015 8:32 AM

Yeah I'm gonna have to keep searching around for a transformer that meets those specs or possibly get two 18vCT and see where that gets me. I've proven the rest of the system works so I've shut it down and removed the transformers for now. And the wife's back in 2 days, so it looks like I'm done tinkering for now. :(



#15 mthompson OFFLINE  

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Posted Wed Mar 18, 2015 9:39 AM

The ebay link in post #6 above has an original transformer for $10, unless you're looking for something new.



#16 eobard OFFLINE  

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Posted Wed Mar 18, 2015 10:27 AM

I saw that and was looking at one other deal too. Thing is I'm in Canada so the shipping would hammer me. But I hemmed and hawwed about it and finally pulled the trigger. WTH, no guarantee the next transformer(s) I buy would be close enough and I might wind up spending lots more before finding a suitable substitute anyhow so I bought it.

 

Intellivision console: $10CAD

replacement transformer: $10USD

 

paying more than those two totals for shipping: Disgustingly Priceless! :roll:



#17 freewheel OFFLINE  

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Posted Wed Mar 18, 2015 2:45 PM

Whereabouts in Canada? Some folks here may be able to help. Everyone has a busted system somewhere (and it's usually different stuff that's busted).



#18 eobard OFFLINE  

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Posted Wed Mar 18, 2015 7:24 PM

Hamilton but I've aready bought the transformer from the link above.



#19 HunterZero OFFLINE  

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Posted Wed Mar 18, 2015 8:26 PM

Again I would imagine an 18V with center tap transformer would still end up delivering a voltage that is a bit too high (the unloaded voltage of such a transformer would likely still be over 20V).

 

 

Sometimes, the feeling of a job well done that comes with a successful repair, and that you've rescued one of these old consoles from landfill is enough to justify the cost of parts. Even more so if you successfully get it past the significant other. ;)

 

- J



#20 Black6104 OFFLINE  

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Posted Fri Nov 24, 2017 3:15 PM

I've been looking online now for a while trying to figure out whats wrong with my intellivision, but i haven't had any luck. So im gonna ask on here now. When i set it up, the TV will display either a black screen, or it will go through Static in this order - Thick Black and white Lines, Medium Black and white Lines, and then Thin black and white lines. It does that a few times before switching back to a black screen. It does react to the reset button, and the mother board is getting power. I have no idea what is wrong with it. It had been working fine up until a few days ago. Any ideas?



#21 mr_me OFFLINE  

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Posted Sat Nov 25, 2017 5:54 AM

Maybe start by checking power supply voltage as well as continuity through the ribbon cable to the main board. The service manual can be found here.
https ://console5.com/wiki/Intellivision

Then visually check/clean the mainboard for problems.

Try a cartridge that plays music at the titlescreen or try MLBaseball and press disc for sounds.

#22 IMBerzerk OFFLINE  

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Posted Sun Nov 26, 2017 2:26 PM

Fixing an Intv can be easy, and can be hard as he'll. You first need the manual to start with. I realize you don't have an oscilloscope but many of the problems are not on the chip level.

You may need to do some soldiering, open up the pcb... voltage testing...etc. there isn't a quick fix or most common problem with these thing like you're trawling for. I've fixed many of these and found different problems with each unit...BUT... I will say this. Put the unit into a standard configuration so that you know all the basics are working. Get all the readings up to standard as to expected in the manual... if you can't, then you're already on track.

So.. the color flash issues sou nd like bad cart to interface. Clean the crap out of the cart, spray contact cleaner into the receptacle and work the hell out of it. Now turn in on... check all voltages into the main PCB. If they are low or high, stop there. You found the problem. If they are normal... could be a STIC chip issue..or an EXEC chip. Read

But again.. asking is ok, but to really help you, the basics need to be covered.

JR

#23 IMBerzerk OFFLINE  

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Posted Sun Nov 26, 2017 2:31 PM

I will toss 1 very common problem at you to check.

Take a close look at the soldering points of the two massive capacitors on the main power board. They do fail and are a common headache that us easily fixed with resoldiering.





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