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Sega Blast City PSU help

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streetlights

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Hello...I just picked up a sega blast city and am pretty new to arcade cabs...the blast works with my regular cps2 games, but doesn't work with a tekken tag pcb that i just picked up.

The intro to tekken tag works, and the game played once, but other than that i get a white screen, or a weird mixed up screen when i try to play the game...i bought a multi meter and tried to check the psu to see if there needs to be an adjustment, but i cant figure it out...the psu is the original psu that came with the blast city...

When i checked the board while the game was running I initially got a 4.6 reading (black probe on the first pin of the jamma harness, red probe on the third pin of the jamma harness), i adjusted the power on 5v adjustment screw on the psu to try to get a 5.0 but the most i got up to was 4.9 when the 5v adjustment was maxed out.

There are two adjustments, one says 3.3v and the other says 5v, I'm pretty sure I'm doing something wrong as I am new to the machines and I don't know much about checking power. Any help/advice would be appreciated!

thanks!
 
Blasts are getting to the age where recapping the PSU is going to be necessary on a lot of them, especially for high power draw games. I recently recapped mine for this exact reason, there's a thread on here somewhere I made about it.
 
cool...just checked out your thread...that work is for sure beyond my abilities right now!

can you tell me how I can check the power coming out of my psu so I can assess if there is an issue with the psu? most of my cps2 boards are functioning properly, it's the tekken tag that I just picked up that isn't working...the seller indicated that the board was functioning properly...
 
If you're having to crank the 5v pot on the psu to even hit or come close to 5v then a recap is in order for sure. You can check at the jamma edge what the psu is pumping out. Which you said you already did.
 
ahhh...okay...i dont know a thing about recapping...

does anyone have any suggestions for a new replacement psu that i could purchase while i try to figure out how to recap?
 
the proper way to test and adjust voltages is explained in this video:
(start around the 1:30 mark)

On boards like your Tekken Tag you can test on the chip like you see in the video, but on boards like the CPS2 where you can't get to the chips then you can test it on the edge connector and turn it up a bit beyond 5 (between 5.05 and 5.10).

the 3.3V adjustment is for JVS games like the NAOMI that require a 3.3V input in addition to the 5V input.

While you can't adjust it you should also check that your 12V and -5V outputs are within spec (+/- .5V of 12V and -5V respectively) Not all PSUs have a -5V, but it's required for audio amplification on some games (like Mortal Kombat)

If all 3 outputs are in spec then your PSU is working correctly.


---------
As for a cap kit. start by pulling the PSU out and removing the cage so you can see the PCB. You'll want to look at the electrolytic capacitors (the ones shaped like soda cans) and check if they look like they're puffed out on top or worse (leaking out the bottom, or corroded)

In the picture below 2 of these caps look good, and 3 are definitely bad:
elko.jpg



Some caps can be bad while showing no physical signs, but if ANY caps on your board are bad it's a good idea to replace them all.

All you do is buy new capacitors to replace the ones on your power supply, use a soldering iron to remove the old ones then solder in the new ones.

A lot of places sell "kits" for this which is a bag full of all the specific caps you need to do a particular PCB and usually a piece of paper with a map or chart describing where they all go.... hence the term "cap kit"

if no one makes a kit you can try to find a cap list or cap map online and buy the caps yourself through digikey.com or mouser.com The best caps to use are high-temp caps (rated for 105 deg or higher) and name brand such. You can find a list of high quality cap brands here: http://www.tomshardware.com/reviews/power-supplies-101,4193-5.html

If you've never soldered before, then the kind of soldering you do with a cap kit is VERY EASY, it's the perfect kind of job for someone just learning. Don't start on your PSU though, find a junk PCB with some caps or other similarly mounted components, watch some youtube videos on soldering techniques and practice removing and reinstalling the parts on the junk board. I can't imagine it will take very long before you get the hang of it.
 
Seconded... Through hole soldering is a useful skill to have. I recommend a good solder sucker (I use soldapullt brand, there are cheaper alternatives, but these seem to last decades), a good pair of flush cutters (Plato esd), and a temperature controlled iron (I use a hakko 936, but I've read of a hakko clone that the rca crowd uses that's like 15 used, aouye makes a good one too). Get good solder with rosin already in it - 60/40 mic is a good choice. I just bought a 1lb spool of Kester 60/40 about 5 years ago for $30. Still using it.

Note that you don't need a temperature controlled iron to recap a board - you can use your radio shack special $10 iron - but if you're serious about it, spend the $60-80 and pick up a nice used temperature controlled iron. It'll become an indispensable tool quite quickly.

Few tips: if pulling a known dead chip or component, ie you don't want to attempt to salvage/save it... Use your flush cutters to cut it out first as often as you can. Then you're just heating the leftover portion of the "leg" and the old solder, and sometimes won't need to use as much heat. Always keep your tip tinned. If you're having a hard time heating old solder, apply a little fresh solder over the old - it helps. For ground plane work, extra heat is almost always needed - still, start on lower heat and turn up the temp as needed. Ie start low, go high. Always remember, too much heat is a bad thing - you just want to heat up the old solder just long enough to remove it. When installing components, you only want to apply enough heat to melt the new solder cleanly around the components leg, and to cleanly fill in the solder hole to make a clean, well-formed joint. This only takes a second or two at most if done right.

This is why it's always best to experiment with an old junk pcb for desoldering, and to then clean the pcb and solder new stuff in there. Those little how to solder kits are fun too, if you want to see the fruits of your labor. For me, I just picked up a blank project pcb and a $3 bag of random capacitors and soldered the in until I got the hang of it and was happy with my work.

Oh! - Also, when done, always always always clean up the leftover rosin Flux - don't just leave it to harden on the board. Its not electrically conductive now, but can reactivate later, causing you issues
 
As said earlier I would not make a PSU recap your first project.

The blast audio amp (model 3 audio amp) is easy since it's single sided traces. The PSU is thru-plated holes and requires some skill and experience if you don't want to botch it. Lots of large traces that will draw the heat right out of your iron.
 
twisted, thanks for the video man...that was super helpful, this is the 2nd time you helped me out!...im gonna test out the chips on my board again later tonight...

thanks everyone else for the great information, im going to start getting caps and trying to figure out if i can source a used, functioning blast psu to play while I try to figure out recapping

appreciate all the help and knowledge
 
There's a few on ebay supposedly tested from yaton6262. I did a best offer of 40 and they accepted. It'll replace the bass fishing ps in mine.
 
Maverick1978 said:
There's a few on ebay supposedly tested from yaton6262. I did a best offer of 40 and they accepted. It'll replace the bass fishing ps in mine.
Click to expand...
Just a word of warning, dude buys out chinese operators, so anything you get from him need a massive bath. Those PSUs prolly need a recap too. Dude used to send MVS carts in tampon boxes. Tampon. Boxes.
 
Rofl! Thanks for the heads up. TBH, I figured that I would need to bathe the entire thing - I know that most of these things come from Japanese arcades, and nothing against smokers, but uh... that shit is NASTY :)

I rather planned on recapping it anyway. For the bit of time and few bucks it takes, I'd rather know that my equipment is safe. The original Sega Bass Fishing supply I have works well anyway - just isn't what I want in my finished product.

Assuming that I ever get my monitor and harness situation worked out, I mean.
 
kidpanda said:
Maverick1978 said:
There's a few on ebay supposedly tested from yaton6262. I did a best offer of 40 and they accepted. It'll replace the bass fishing ps in mine.
Click to expand...
Just a word of warning, dude buys out chinese operators, so anything you get from him need a massive bath. Those PSUs prolly need a recap too. Dude used to send MVS carts in tampon boxes. Tampon. Boxes.
Click to expand...
Yaton MVS Carts. 60% MVS Cart, 40% Spiders.
 
Hah! I guess I'm numb. One of my other hobbies is vintage computers. I won't even begin about some of the horrors I've found in those over the years :)
 
nem said:
Blast PSU doesn't have -5V, so don't worry about that.

Unless you find someone selling a recapped Blast PSU (unlikely), your best bet is to do it yourself. Wiring a different PSU in a Blast is huge amount of work.

List of caps can be found here:

http://wiki.arcadeotaku.com/w/Sega_Blast_City_PSU
Click to expand...
if you have a cab/psu and you need -5v you can wire in a "Negatron" great little device that has adjustable -5v and is powered off the 12v rail. Guys check it out if you like. It can be put right on the JAMMA harness :)
 
Maverick1978 said:
Seconded... Through hole soldering is a useful skill to have. I recommend a good solder sucker (I use soldapullt brand, there are cheaper alternatives, but these seem to last decades), a good pair of flush cutters (Plato esd), and a temperature controlled iron (I use a hakko 936, but I've read of a hakko clone that the rca crowd uses that's like 15 used, aouye makes a good one too). Get good solder with rosin already in it - 60/40 mic is a good choice. I just bought a 1lb spool of Kester 60/40 about 5 years ago for $30. Still using it.

Note that you don't need a temperature controlled iron to recap a board - you can use your radio shack special $10 iron - but if you're serious about it, spend the $60-80 and pick up a nice used temperature controlled iron. It'll become an indispensable tool quite quickly.

Few tips: if pulling a known dead chip or component, ie you don't want to attempt to salvage/save it... Use your flush cutters to cut it out first as often as you can. Then you're just heating the leftover portion of the "leg" and the old solder, and sometimes won't need to use as much heat. Always keep your tip tinned. If you're having a hard time heating old solder, apply a little fresh solder over the old - it helps. For ground plane work, extra heat is almost always needed - still, start on lower heat and turn up the temp as needed. Ie start low, go high. Always remember, too much heat is a bad thing - you just want to heat up the old solder just long enough to remove it. When installing components, you only want to apply enough heat to melt the new solder cleanly around the components leg, and to cleanly fill in the solder hole to make a clean, well-formed joint. This only takes a second or two at most if done right.

This is why it's always best to experiment with an old junk pcb for desoldering, and to then clean the pcb and solder new stuff in there. Those little how to solder kits are fun too, if you want to see the fruits of your labor. For me, I just picked up a blank project pcb and a $3 bag of random capacitors and soldered the in until I got the hang of it and was happy with my work.

Oh! - Also, when done, always always always clean up the leftover rosin Flux - don't just leave it to harden on the board. Its not electrically conductive now, but can reactivate later, causing you issues
Click to expand...
Another trick that works with ElectrolyticCapas thar are through hole on pcbs that just dont want to come out is putting your iron on the solder side leg and with your other hand push the cap in the other direction while it is being heated. I.e. if you are trying to remove a stubborn left leg, add some heat to it and holding the top of the cap, pry it to the right. You will see and feel the leg go through. Do the same to the other leg until you rock them both off the board. Once it is removed, apply a bit of new solder to the holes and flood them a bit, then, while still liquified, use your solder sucker and you should get a nice clean hole to purt your new cap in. ^^
 
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