I got this thing for $10 figuring either i could pick at it till i figure out whats wrong with it or get help from the various places made available to me through the internet. I come to you guys ;) anyways, like the title says it's dead....and i believe it was an instore demo at guitar center for a while and it worked at one time. So, i took it home and took it apart, started looking at it and everything seems to be in working condition, and after messing with it for a while i realized that the battery gets hot when i have a cable in the input jack. Sound like something is getting crossed somewhere in the input jack or am I off my block?
I'd find the power rail and trace it around seeing if anything's shorting to ground anywhere....
I'd find the power rail and trace it around seeing if anything's shorting to ground anywhere.... Get a schem and check all the parts that connect to V+ and make sure they're not shorting...
extreme noob here, whats the easiest way to do that?
Find the Red wire and then find the black wire....
Where the red connects to the board, that trace is the source of power....make sure that it's not shorting to the black wire,.... also find any components that may look fried, unsolder one end, and then see if the circuit is still shorting
no fried components, can i get some help finding a schem?
cant find one and been looking for a while
Check the Schematics link at the top of the page,,,or Tonepad.com
it's definatly worth getting it going, I had one awile ago and it got stolen. Keep working at it, I've been looking for a cheap one for ever.
You might want to put that aside and try building a few simple distortions. That might not have been what you were planning on doing but it's lots a fun :twisted: A few simple builds would get you used to used to trouble shooting and terminology and what not.
Here's a link for the schematic.
No no, seriously.... here's the link.
http://www.tonepad.com/project.asp?id=13
http://www.tonepad.com/project.asp?id=7
One of them is for a phase 45 and the other is for the phase 90. (The phase 90 is just a two stage 45)
I included them both because I can't remeber which was which and I though you might be interested.
look inside and find out if they installed a diode to prevent reverse polarity (one that connects to the + and -)...could be that it failed as a short. Unsolder one of the leads and check the pedal again...if it works, you know what it is...if it doesn't let me know.
Alf
the diodes look fine....and although they're close to the leads i cant actually see anywhere where - and + would be connected through one. How do i go about testing if stuff is grounding out? I'm borrowing a friend's voltage meter now....will that do the trick?
A visual inspection won't tell you. Measure the continuity between the 2 leads in the diode. Do this test with the meter probes reversed also i.e., 1st time put the red probe on the anode and the black in the cathode and check...then reverse the probes and do this again...If there's a short it'll be very obvious....
my recommendation, unsolder 1 lead of that diode and test the pedal again.
Alf
well i unsoldered one side of both leads, actually breaking the larger of the 2 diodes on accident. whoops. anyways now the led comes on so i figure we're making progress in the right direction.....no phase effect though. now when i take a wire or something and connect the solderpoints before and after the diodes i can get short phases, only after contact and unconnecting it. we're close i can feel it....should i get on ordering some new diodes or what? do i even need them?
well i popped both diodes out and now i need help figuring out what their values are....one is broken so testing that one probably wont work. Or, can I assume that the values found in the schematics/layouts on tonepad are the same? only problem is they use 2 different sets. should i assume the ones on the phase 90 are what im looking for?
so you have a digital camera? if so take a pic of the board and I'll check on my side...I have 2 Phase 90 here.
Alf
I don't know what version you have, but...
The one in the corner of the board, which is usually copper coloured, is a 1N914. The one near the trim pot, which is often a black one, is a 5.1V zener (most likely a 500mW type).
I think you have destroyed the zener which means you will have to adjust the trimpot to restore the proper JFET biasing.
Quote from: chokeyouwell i popped both diodes out and now i need help figuring out what their values are....one is broken so testing that one probably wont work. Or, can I assume that the values found in the schematics/layouts on tonepad are the same? only problem is they use 2 different sets. should i assume the ones on the phase 90 are what im looking for?
There are 2 diodes in the circuit...if you take the Zener out it'll affect the the bias on the Jfets. That one has to be reinstalled - its a 5.1V Zener.
Do you have a reissue Phase 90 or the older version? and yes, use the Tonepad schematic...D2 is the zener...I D1 is the one that had failed as a short (my best guess).
Alf
they're both like orange/red/black....ones about 3mm the other is 4mm.. thanks for the help
My guess is that the largest one is the Zener...which one did you break?
Alf
the bigger of the 2
you never said if you have an older Phase 90 or the reissue.
Alf
its the reissue, sorry
Well, at least no wires to worry about on that one, only the battery connect, which hopefully you didn't reverse. Does it have any caps or reisitors removed. Somebody could have done the script mod to it, and instead of pulling the resistors and caps, they might have clipped one end, and accidently shorted it out on another component.
nah there wasnt any evidence that it had been modded or anything. but about that battery thing, when it wasnt working one of the things i tried was reversing the battery jumper....thinking maybe it was backwards when i got it. that didnt screw anything up did it?
There are 2 diodes near the battery clip socket in the circuit board. The diode nearest to the clip is the Zener...you need that one. The next one is the diode used to prevent reverse polarity from damaging the pedal (...whatever...). That one must be dead in your pedal...if you test continuity on it it might display a short....take it out.
Check this pic...in the lower left corner you'll see a silver-like diode (that's the Zener):
http://acapella.harmony-central.com/forums/attachment.php?s=&postid=6750568
Once you put a new zener (assuming that's the one you broke), the pedal should work. If you get a clean sound without the phasing it means that the LFO is not working (the dual opamp may be dead) OR the Jfets are dead (this happened to the one I have in my hands rignt now). Just replace the Jfets and you're ready to go.
That's all I have for now.
There are 2 diodes near the battery clip socket in the circuit board. The diode nearest to the clip is the Zener...you need that one. The next one is the diode used to prevent reverse polarity from damaging the pedal (...whatever...). That one must be dead in your pedal...if you test continuity on it it might display a short....take it out.
Check this pic...in the lower left corner you'll see a silver-like diode (that's the Zener) and the one on top of it is the regular diode:
http://acapella.harmony-central.com/forums/attachment.php?s=&postid=6750568
Once you put a new zener (assuming that's the one you broke), the pedal should work. If you get a clean sound without the phasing it means that the LFO is not working (the dual opamp may be dead) OR the Jfets are dead (this happened to the one I have in my hands rignt now). Just replace the Jfets and you're ready to go.
That's all I have for now.