Stock Pedal Problems.

bumblebee · October 17, 2008, 07:33:21 PM

I have a MIJ DS-1 with the single inline opamp TA7136P(?). The problem is that when I turn it on it plays perfect for about ten minutes then the LED starts to fade out and the distorted signal starts to be less distorted finally ending up sounding like an OD with a weak battery, if I unplug it and leave it sit a while then re try it it plays perfectly again.

Any ideas on whats going on? I have no experience with opamp effects BTW.

I was going to get if fixed by BOSS but its cheaper to just buy a new/old MIJ again but I'd rather try fix it myself.

Theres a schematic here:http://www.godiksennet.com/images/sch/DS1PG2.jpg

Thanks!

aron · October 17, 2008, 07:56:08 PM

Is this with battery or power supply?

bumblebee · October 17, 2008, 08:19:43 PM

Its with a battery cause I don't have the right power supply for it, the battery is over 9 volts.

bumblebee · October 20, 2008, 06:04:14 PM

So no one has any ideas then?

sasuke_kun12 · October 20, 2008, 06:33:09 PM

Might sound like a stupid question but have you tried just a 9V battery like duracel?

bumblebee · October 20, 2008, 07:08:19 PM

yea, Ive tried a few different batteries and measured the volts after the symptoms start happening.

aron · October 20, 2008, 07:34:05 PM

What is the voltage of the battery when this happens? You can also use an audio probe to listen to the level at C2, C3, C5 C9, C13 and C14.

That will tell you where the drop off is occurring.

bumblebee · October 20, 2008, 08:30:55 PM

When I was trying different batteries they were all cheap chinese made ones, one said it was alkaline although due to what just happened I highly doubt it was....I just went to the store and bought some duracell alkalines, I had one in the DS-1 for around 25 minutes and no problem, so it seems as though it needs an alkaline to work right. I just hope that all it was and I have no more problems. Time will tel when I sit down to play for a longer period of time.

Zben3129 · October 20, 2008, 08:57:14 PM

Quote from: bumblebee on October 20, 2008, 08:30:55 PM
When I was trying different batteries they were all cheap chinese made ones, one said it was alkaline although due to what just happened I highly doubt it was....I just went to the store and bought some duracell alkalines, I had one in the DS-1 for around 25 minutes and no problem, so it seems as though it needs an alkaline to work right. I just hope that all it was and I have no more problems. Time will tel when I sit down to play for a longer period of time.

I'm willing to bet this was the problem, did the batteries you were testing with feel light?

And if it is not the battery, the next place to check would be electro caps I think

Zach

bumblebee · October 20, 2008, 09:10:31 PM

feel light? not really.

why would alkaline work and non alkaline not work? considering they are new and over 9volts?

Zben3129 · October 20, 2008, 09:15:44 PM

Quote from: bumblebee on October 20, 2008, 09:10:31 PM
feel light? not really.

why would alkaline work and non alkaline not work? considering they are new and over 9volts?

I've found that the cheap dollar store batteries have a horrible battery life (go figure), and are often lighter than good batteries. I am assuming they don't have as much of something that would give a nice 9v its good characteristics.

Also, I would imagine that it isn't an alkaline vs non alkaline problem, so much as a crap vs. noncrap issue. While a cheapo battery may be giving you 9v, it won't have as good of a maH (milliamp * hour) capacity, making it... well... crap.

You could be draining it in those first 10 minutes, or just working it too hard with the circuit. A decent battery will easily hold up to what you are asking it to do, therefore no (hopefully) pedal problems

Zach

bumblebee · October 20, 2008, 09:41:35 PM

Ah ok.

I buy boxes of 20 of non alkaline batteries cause I mostly have fuzz pedals and El Cheapo batteries for fuzz seems to be fine and I've gotten so used to using them battery problems didn't even cross my mind this time.

I've had some cheap chinese battery in my woolly mammoth for almost 2 years and its still over 9 volts.LOL (the woolly mammoth only draws 0.0004 amps so thats part of it too)

Anyways thanks to those who mentioned alkaline batteries, it jared mi brainz into action.

hopefully the problem is solved.

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Stock Pedal Problems.