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Smack2k
February 11th, 2016, 10:40 AM
I have a Model 1 Sega CD that wont power on. I know the fuse is bad, but to verify that was all it was, I bridged the fuse with the intent of making sure the device would work once I fixed it (saw this in YouTube Video where the guy bridged it, checked power and then shut it off again). In my case, even with the bridge, I dont get power. I will get a flash of power that lasts for a split second every 15-20 times I power on the genesis. I know the power supply is good as well, as its been tested on several Model 1 Genesis and they all work fine.

Taking a Multimeter over the board, I cant any readings from the capacitors at all, and I cant imagine every one of them is bad..I do get a reading from the chip (not sure what exact type it is) that is in front of the fuse and diode if you are looking at the Sub Board. The Diode also tests fine for continuity as well.

Any ideas on what I can check / do next? I know I need the fuse and I ordered a couple of those so I can install it in. But I dont think or know if that will fix my issues here. The boards were cleaned of all dust / particles as well. I reseated the cables between the Sub Board and Main Board and Main Board and CD-ROM and cleaned the contacts from where the Main Board Connects to the Side Panel that also connects the Genesis

kyodai
February 11th, 2016, 02:34 PM
Pretty hard to diagnose this without any tools from a thousand miles away... Good chances that a capacitor blew and spilled its content over some board which usually does not improve stuff (Conductivity is only good where it is supposed to be). Maybe cleaning will go in excess of just dusting it off to make sure no condensator contents were blown and unfortunately spread conductivity where it was not supposed to be... The multimeter will stay your friend here. If the diode is still fine then the error will be somewhere after that diode... You can bridge the fuse, doesn't matter if your power supply is reliable...If the power comes through a fuse or through a rusty nail doesn't interest the circuit much...

Smack2k
February 12th, 2016, 03:41 AM
The Capacitors all look fine, no bulging, cracks, or anything else on them. No residue or crap on the boards from them either, even before cleaning. I will have to keep looking over the board.

Capt. 2110
February 14th, 2016, 10:12 AM
Bad capacitors are Sega's favorite thing. I'd recommend buying this and testing the caps anyway, since these are always useful. I own one, and it's pretty good for what it is: http://www.amazon.com/Honeytek-A6013L-Capacitor-Tester/dp/B0036FQ3FW/ref=cm_cr_pr_product_sims?ie=UTF8
In the case of things like tube radios, the caps can fail without any sign of failure, so it's possible some caps have failed anyway. It also might be dead in general, as seen with one of my Game Gears: http://www.smspower.org/forums/14962-WhatDoR47uf50vCapsDo
It still doesn't work. :\

Smack2k
February 14th, 2016, 04:43 PM
I bought a cap kit for it and will see how that goes when they and the new fuse arrive....after that, I give up and will move on...

But seeing that quick flash of power is what keeps me wanting to find the issue...

I still dont know why I get no readings when trying to test the capacitors, nothing at all from any of them. They cant all be bad.

Stone
February 14th, 2016, 06:04 PM
How do you test a capacitor that's still in circuit?

Malc
February 15th, 2016, 02:45 AM
I still dont know why I get no readings when trying to test the capacitors, nothing at all from any of them. They cant all be bad.

How are you testing them ?, Generally it's advised to remove caps from circuit before testing them, ESR meters can't test caps in circuit in all situations.

Smack2k
February 23rd, 2016, 02:54 AM
I think that is my issue...I am trying to test them in the board.

I just bought a new cap kit and fuses for the Model 1 and going to work on re-caping the boards and see how that goes.

Smack2k
September 22nd, 2017, 03:08 AM
So after nearly a year and a half, I pulled this thing out again to try and fix it...

Replaced the fuse and a resistor that sits next to the fuse on the power board. Both seem fine after I tested them (the fuse has continuity and the resistor is testing within its range). System still doing the same thing where it power on for about 1 second and then power off. I can hear the CD Unit start to make a little noise then nothing. The power board and main board look perfectly fine, there is no residue to blown caps on either of them. I have cleaned all the connectors in the system really well (connectors from CD to Main Board, Power Board to Mail Board, Main Board to Genesis) and my issues remain. I didnt do the full re-capping yet as I really dont think the caps are the issues as they all look really good, no bulging, nothing leaking, no cracked solder....

Could the CD Unit possibly cause this issue to happen? I am going to pull it out and take a look at it to re-align it and make sure the laser assembly moves up and down like it should, but wasnt sure if anything on the CD Until could cause the issue I am having.....almost like a short is causing it to power off....

Stone
September 22nd, 2017, 03:37 AM
I didnt do the full re-capping yet as I really dont think the caps are the issues as they all look really good, no bulging, nothing leaking, no cracked solder....Looking at a cap is not going to tell you everything you need to know. Many caps fail without any visible signs whatsoever.

GottaLottaStuff
September 23rd, 2017, 11:52 PM
Did you try bypassing the power switch?

GiGaBiTe
October 2nd, 2017, 11:26 AM
I know the power supply is good as well, as its been tested on several Model 1 Genesis and they all work fine.

If you're using the original fat wall wart which uses a fat transformer, check the voltage. The old linear DC transformers have a tenancy to drift upward in voltage, and can be out of spec in as little as a year.

For some perspective, my original Genesis wall wart from 1990, which is supposed to put out 9v DC now puts out 17.4v DC. The Naki wall wart for my Sega CD I bought in 1993 is in the same boat, it was originally 9 also but puts out 22v now. needless to say I don't use them anymore, they're in the bin of "do not use" wall warts.

Another thing you need to be aware of is that both the Genesis and the Sega CD barrel connectors for power are center negative, with the outside positive. If you plug a modern power supply into either, you're likely to destroy your genesis if you don't reverse the polarity. The modern standard for barrel DC connectors is center positive, but back then it was center negative.