ZPA0.5 Needs work

jbob0124 · Post by **jbob0124** » Fri May 07, 2010 12:19 pm

I bought a used zpa0.5 and it came in today, the first thing I did was take the cover off and look at the boards. I found a few spots that are questionable. Unfortunately I don't know enough about the boards to know whats what, although I know whats out of place. I snapped a few pics, looking for opinions on it. Going to go hook it up to see if it works.

Post by **stipud** » Fri May 07, 2010 12:24 pm

Random, ugly jumpers are pretty common actually in the older PG amps. I don't see anything really concerning, but I am no ZPA expert.

Stryker · Post by **Stryker** » Fri May 07, 2010 1:57 pm

I'm no expert at all, but shouldn't those caps be replaced first?
They look questionable to me.....

jbob0124 · Post by **jbob0124** » Fri May 07, 2010 2:15 pm

The caps themselves look pretty clean, the board under it looks a little on the dirty side, but not bad.

I've got another pic of the board near the balance connection and R channel connection. I noticed two pieces that look like they have melted. (not sure if they are or not)

todd217 · Post by **todd217** » Fri May 07, 2010 2:23 pm

my caps looked fine also http://phoenixphorum.com/burnt-zpa-0-5- ... 13017.html change them

jbob0124 · Post by **jbob0124** » Fri May 07, 2010 2:30 pm

Im not denying the fact that they are probably old and need to be replaced, but before I go replacing anything I want to see if I can get this working easily/cheaply otherwise Im going to try and get my money back. This was supposed to be in good working condition and was supposedly bench tested just before it was sold.

I don't mind putting the work into fixing it as long as it isn't going to cost me an arm and a leg. I already spent a good amount for it.

yeddy · Post by **yeddy** » Fri May 07, 2010 2:56 pm

Aren't those jumpers to make your inputs grounded or floating depending on what you use for inputs? Grounded for RCA or floating for the rj45? Your amp is clearly grounded for RCA inputs. Correct me if I'm wrong guys, I'm just kinda guessing, but it looks right to me...

jbob0124 · Post by **jbob0124** » Fri May 07, 2010 4:16 pm

Well I managed to get both channels working, but I have to turn one channel all the way up to match the output of the other channel which is turned all the way down. Still only one fan running, I think im giving up for tonight and will probably mess with it more tomorrow.

jbob0124 · Post by **jbob0124** » Sat May 08, 2010 8:11 am

Well I managed to get both channels working correctly, apparently the crossover chip wasn't sitting just right. Eventually I will replace that with the zpaxo. Now I just have the fan to figure out. Hopefully its just a bad fan.

Also, what are the four yellow adjustable knobs for? I've never really messed with those and have been curious...

shawn k · Post by **shawn k** » Sat May 08, 2010 8:31 am

If you get a ZPAXO I will buy your blank chip. Let me know!

jbob0124 · Post by **jbob0124** » Sat May 08, 2010 8:35 am

Sounds good to me. I will let you know.

Post by **Eric D** » Sat May 08, 2010 9:42 am

Your jumpers are melted because they were hand soldered in there. They are so small, no matter what you do the iron gets them too hot and the insulation will melt. No big deal.

Your caps are bad, real bad. The amp will catch fire soon, without warning.

There looks to be some damage on the power supply section. Maybe a FET or two was replaced. If so, all 8 need to be replaced for load balancing or the supply will fail later.

Two of the yellow pots are for bias control. The other two are for DC offset control. This is one of the few PG amps with DC offset control, and it is a very nice feature. If they are set right, you should never touch any of them.

Hope this helps.

jbob0124 · Post by **jbob0124** » Sat May 08, 2010 9:57 am

Thanks, I will look into getting new caps and new fets for it. I know I can get the parts from digikey.com, but im assuming the caps are aluminum, then its just a matter of matching up the numbers on the cap. Would it make any difference in getting a higher rated cap, or just stick with the same?

As far as the bias setting, how can I ensure it is set right, or get it set right?

Sorry I know im asking alot of question, this is all new to me, so Im still learning.

jbob0124 · Post by **jbob0124** » Sun May 09, 2010 11:28 am

Anyone have any input on cap size for replacements? Does it make a difference by upgrading to a higher capacitance?

I've read a few post's through out, but nothing definite on it. I don't mind spending the extra money for a higher rated cap if it makes a difference, but if it doesn't then I will simply replace them for what they are.

shawn k · Post by **shawn k** » Sun May 09, 2010 12:22 pm

It's best to replace them with values that are the same as the originals. Really no need change. PG amps, as well as most quality amplifiers, are engineered well and unless you feel you need to challenge the design of an intelligent, or a team of intelligent, engineers then...... well you get the picture

jbob0124 · Post by **jbob0124** » Sun May 09, 2010 1:19 pm

Just wanted to make sure there wasn't a benefit to upgrading before I buy them. I've got 4 zpa's that im going to replace caps on, so I want to make sure I'm getting the right caps before I spend the money.

shawn k · Post by **shawn k** » Sun May 09, 2010 1:27 pm

Nice man! I need to pick up a fourth myself sometime. What are your plans for your system?.. deck, speaks, subs?

southfloridaPGlover · Post by **southfloridaPGlover** » Sun May 09, 2010 1:36 pm

its been switch over to ver .2

southfloridaPGlover · Post by **southfloridaPGlover** » Sun May 09, 2010 1:38 pm

jbob0124 wrote:The caps themselves look pretty clean, the board under it looks a little on the dirty side, but not bad.

I've got another pic of the board near the balance connection and R channel connection. I noticed two pieces that look like they have melted. (not sure if they are or not)

there used to be a switch there when they upgrade the zpa to ver .2 they took out the switch

jbob0124 · Post by **jbob0124** » Sun May 09, 2010 2:40 pm

shawn k wrote:Nice man! I need to pick up a fourth myself sometime. What are your plans for your system?.. deck, speaks, subs?

Not 100% sure, its still in the works...I've got an old Alpine HU that I plan on upgrading at some point. The fronts, I've got a set of 6.5 elite comps. The subs I've got 2 xmax 12's. I don't have any real fill at the moment, but I've got a tx6.0 comp set that I might run off the HU for that. Im running zpa's for the power, two .3's and two .5's.

Its still going to be a while before I actually get my hands into installing...

jbob0124 · Post by **jbob0124** » Sun May 09, 2010 2:43 pm

southfloridaPGlover wrote:
jbob0124 wrote:The caps themselves look pretty clean, the board under it looks a little on the dirty side, but not bad.

I've got another pic of the board near the balance connection and R channel connection. I noticed two pieces that look like they have melted. (not sure if they are or not)
there used to be a switch there when they upgrade the zpa to ver .2 they took out the switch

I thought when they were ver.2 they noted it on the white tag inside the amp?

Post by **Eric D** » Sun May 09, 2010 6:37 pm

I would use 5,600uF caps, as they did not exist when the ZPA was made, but do now, and offer more storage.

southfloridaPGlover · Post by **southfloridaPGlover** » Mon May 10, 2010 7:03 am

jbob0124 wrote:
southfloridaPGlover wrote:
jbob0124 wrote:The caps themselves look pretty clean, the board under it looks a little on the dirty side, but not bad.

I've got another pic of the board near the balance connection and R channel connection. I noticed two pieces that look like they have melted. (not sure if they are or not)
there used to be a switch there when they upgrade the zpa to ver .2 they took out the switch

I thought when they were ver.2 they noted it on the white tag inside the amp?

not on ver.1 that where send in to be upgrade to ver.2