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Dr. Bob
Moderator
Australia
6593 Posts |
 Posted - 04/23/2007 : 13:44:43
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quote:
Originally posted by Goran
Thanks DR Bob!
I�ll have a look inside again, and really check the interconnections.
Hi Goran
Use a really good 3 times or 4 times magnifying glass.
and good lighting, daylight is the best.
Regards Dr. Bob |
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guirat
Silver Member
United Kingdom
186 Posts |
Posted - 04/25/2007 : 03:23:47
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quote:
Originally posted by Dr. Bob
Hi guirat
I had a intermittent with my newly acquired DD-2 - it turned out to be the metal foil shield.
it is plastic coated on both sides, but there are some places on the edges of the foil shield that were exposed & not insulated.
It turned out that the edge of the foil was shorting out the input connector,
Regards Dr. Bob 
Thanks Dr Bob, I think it's that kind of problem. My DD-3 doesn't have a foil shield (maybe it did before I got it, I do know the type you mean as I have seen the DD-2 one) but it does have a rigid clear plastic sheet that goes between the PCB and the removeable metal baseplate - it also has a cutout, presumably so the chip can contact the baseplate. This plastic shield is positioned correctly, in fact it's impossible to seat it incorrectly and close the pedal. I wonder if perhaps the short is something to do with those 2 metal 'prongs' that are attached to the PCB - they contact the outer case, and perhaps they were not in close enough contact? It's a strange one, but I closed up the case and it now works, so I won't open it again unless it fails again. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 04/25/2007 : 03:53:33
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Regards Dr. Bob |
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Goran
Double Platinum Member
Sweden
2203 Posts |
Posted - 05/08/2007 : 10:50:04
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I suppose this is mostly for Dr Bob�.
I have looked a bit into my non-functioning DD-3 again� and there is definitely a short circuit in the DC-input. So it could be the zener after all.
I have read the links written by Stahlhart and he writes that removing the zener will not affect the function of the pedal when used, as long as nothing more than 9V is put in, have I understand things right here?
Can I measure the resistance over the diode and by that way find that it is around 0 ohms in both directions, and therefore broken? Or isn�t it that easy�
Then if so I just clip the diode off, see if DD-3 works again and then look for a replacement diode!???
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 05/08/2007 : 16:34:28
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quote:
Originally posted by Goran
I suppose this is mostly for Dr Bob�.
I have looked a bit into my non-functioning DD-3 again� and there is definitely a short circuit in the DC-input. So it could be the zener after all.
I have read the links written by Stahlhart and he writes that removing the zener will not affect the function of the pedal when used, as long as nothing more than 9V is put in, have I understand things right here?
Can I measure the resistance over the diode and by that way find that it is around 0 ohms in both directions, and therefore broken? Or isn�t it that easy�
Then if so I just clip the diode off, see if DD-3 works again and then look for a replacement diode!???
Hi Goran
The schematic I have is for the DD-2 & the older DD-3.
I can send it to you via PM, if you need it.
It shows the zener D6 from (+) in to ground, it then feeds IC10 a small T0-92 transistor sized, 100mA 5 volt regulator, a 78L05.
I'm guessing that it you have a short on the DC input, it will most likely be the D6 Zener, has shorted,
I would also remove & replace the 78L05 regulator, these are damages very easily.
An it's a good thing, that they do damage easily, as it then sort of protects the reset of the expensive IC's & circuitry.
I use the diode test function on my multimeter,
as zener is like a reversed diode, & will measure open or high in one direction, & about 0.5V to about 0.7V in the other direction.
It is easier to desolder the diode, & measure it out if circuit. and more accurate as well.
I think someone plugged in, the wrong polarity, and maybe the wrong voltage adapter.
The protection zener diode, did it's job well, if it went short.
But if it's open in both directions, then you may have more damage.
I think most of your problem,going by what you have told us, is isolated to the DC in side only.
I have my fingers & toes crossed for you.
It is hard to get a reliable reading on diodes, with just the ohms setting.
I guess I stopped using the ohms setting many years ago.
But if you have a shorted diode, then you will see close to zero ohms.
Use he diode setting if you have it.
If the zener is open circuit, then i guess you'll see that as well.
I really do hope that your zener went short.
Like I asked you, please desolder & remove the diode to test it.
you may even see a crack in the body of the diode.
As far as running the DD-3 without the protection zener,
Stahlhart, is correct it will still work.
But Please be very careful that you use the correct Voltage & polarity plugh pack adapter.
measure the output voltage of the 78L05 regulator relative to the negative or ground.
If it's faulty, you most likely will see no output
The 78L05 is a cheap regulator, it has the same pin-outs as its big brother, the 7805.
In a pinch I sometimes use a 7805, in place of a 78L05, I have done this to a few guitar tuners & rack units, when I'm out & it's Sunday & nowhere to get parts, & the gig has to go on.
If there is very little room, in the unit, that I'm fitting the bigger 7805 to, then I sometimes cut of the top of the metal tab,
It's a 1 Amp (1000mA) regulator & the 78L05 is only 100mA, so it won't overheat.
Ok I'm up for a while if you need the schematic.
Good luck - we all want to see you get it repaired.
Don't rush, Work slow, & double check everything.
If it was a wrong polarity & voltage adapter.
Also look at the 100uf 16 volt C51 cap in parallel with D6, if the adapter was higher than 16V it may have damaged the cap.
Not many parts on the input side, so even if you have more that one fault, it wont be expensive to fix.
If your using a PSA 9v DC regulated adapter, then you can also temporarily remove C51 as well, it will still work.
But please, do check the 78L05's output voltage.
Regards Dr. Bob |
Edited by - Dr. Bob on 07/28/2008 15:33:11 |
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Goran
Double Platinum Member
Sweden
2203 Posts |
Posted - 05/09/2007 : 07:45:09
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Thanks a lot Dr Bob, again�.
What should we do without you at this forum�
I have the schematic so that�s no problem, my DD-3 is identical inside to my DD-2 (so in reality I don�t need to fix it, but I don�t like broken things�).
The problem is that I�m not that good at electronics and has to build up some courage� I�m very good at working on guitars, wood, metal etc and doing electronics in passive guitars. But subtle electronic circuits are something different�
When my mind is ready for it I will do what Dr Bob suggests (anytime now I hope) and report the result.
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Goran
Double Platinum Member
Sweden
2203 Posts |
Posted - 05/10/2007 : 07:16:01
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YES!!! IT WORKS!!!
Yesterday I got myself together and decided to open my DD-3 up, find the zener, cut it off and see if it worked.
Well, finding the zener took me about 15 minutes� there are a lot of stuff inside a DD-3, and they are small too, and really crammed�. And I started looking at the wrong end of the PCB�
When I found the zener I really saw that the solder had melted at one of the legs, I didn�t measure, it was too crammed there, just cut one of the legs off.
Then I tested with my Cioks supply and there was no short circuit at the DC-input, Cioks has a LED that indicates a short circuit. Great!
Then I thought it was best to measure the voltages from the DC-in, but where there was supposed to be voltage there wasn�t any�.I measured and measured, followed cables, looked at the PCB with magnifying glass� for about an hour�. I was ready to throw DD-3 out of the window, but instead gave up completely, screwed the bottom plate in place and put it back in the �archives�. An hour later I thought maybe I should give it a try with guitar and amp, I did, and it worked!!!
Then I realised that I had been stupid enough not to put jacks in the pedals in/out when measuring�..
Thanks a lot Dr Bob for all the tips, all the encouraging and all the words you have posted to this forum regarding my DD-3!
By the way, are there any alternative names for the zener?? As I couldn�t find that part number in an electronic catalogue.
I plan to solder a new zener even if it�s crammed like hell there�.
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Edited by - Goran on 05/10/2007 07:33:45 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 05/10/2007 : 07:18:25
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Hi Goran & guys
If you were a bit close Goran, I'd try to fix it for you. 
Take your time,
look twice,
use a small tipped soldering iron, about 40 watts or so,
don't apply too much heat
get some good quality rosin core solder. I use 0.71mm & 1.2mm dia solder.
Get some solder wick, to help you remove the components.
you can use Metho on a cotton ear bud to clean up any excess rosin (solder flux)
that get on the PCB.
Most of all, don't use a corrosive or activated flux, on PCB's it will slowly eat the tracks away, & is difficult to clean up properly.
Corrosive flux is used in plumbing solder.
Get a good glass magnifying lens, & work under good lighting.
You will do OK.
Just double check your work.
A good hint, is to take some photo's before you do any work.
This little hint, has saved me a few times, especially, if a wire magically breaks off.
Regards Dr. Bob
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Goran
Double Platinum Member
Sweden
2203 Posts |
Posted - 05/10/2007 : 07:38:08
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Dr Bob� we wrote & sent at about the same moment �.
I have a decent soldering iron and the right solder. Even if it�s not like a Fuzz Face I will be able to do this soldering properly, I have gone some soldering course a couple of decades back� and changed pickups etc on plenty of guitars.
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Edited by - Goran on 05/10/2007 07:39:32 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 05/10/2007 : 08:52:42
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quote:
Originally posted by Goran
YES!!! IT WORKS!!!
Yesterday I got myself together and decided to open my DD-3 up, find the zener, cut it off and see if it worked.
Well, finding the zener took me about 15 minutes� there are a lot of stuff inside a DD-3, and they are small too, and really crammed�. And I started looking at the wrong end of the PCB�
When I found the zener I really saw that the solder had melted at one of the legs, I didn�t measure, it was too crammed there, just cut one of the legs off.
Then I tested with my Cioks supply and there was no short circuit at the DC-input, Cioks has a LED that indicates a short circuit. Great!
Then I thought it was best to measure the voltages from the DC-in, but where there was supposed to be voltage there wasn�t any�.I measured and measured, followed cables, looked at the PCB with magnifying glass� for about an hour�. I was ready to throw DD-3 out of the window, but instead gave up completely, screwed the bottom plate in place and put it back in the �archives�. An hour later I thought maybe I should give it a try with guitar and amp, I did, and it worked!!!
Then I realised that I had been stupid enough not to put jacks in the pedals in/out when measuring�..
Thanks a lot Dr Bob for all the tips, all the encouraging and all the words you have posted to this forum regarding my DD-3!
By the way, are there any alternative names for the zener?? As I couldn�t find that part number in an electronic catalogue.
I plan to solder a new zener even if it�s crammed like hell there�.
Hi Goran
you must have posted this before, while I was typing up the message after yours.
Congratulations   
you wrote:
I realised that I had been stupid enough not to put jacks in the pedals in/out when measuring�..
Do you know how many times, I have done the same thing, & forgotten to inset the input jack, which is also the on-off switch. 
More times, that I care to remember. 
By the way, are there any alternative names for the zener?? As I couldn't find that part number in an electronic catalogue.
It might be just under the standard diode section, in it's own area.
The part number is a Boss internal stock number. it protects your DD-2, from reverse & over voltages.
While I don't have a cross reference to Boss part numbers.
The number is RDF11FB-3 --- I'm guessing it's an 11 volt 1 watt zener
as the early DD-2 & 3 run off a 12 volt unregulated ACA power adapter.
Comercial part numbers are something like 1N47xx, where the xx changes with voltage, but the xx number has no reference to the voltage of he zener it self,
eg, a 1N4747 is a 18 volt 1 watt sener.
They can also be something like BZX... or BZY... depending on wattage.
Maybe Stinkfoot, Bossarea or someone else, will confirm this.
I just went & checked for you......
A RD11FB3 is a 11 volt 1 watt zener
here are some links to help prove it.
http://www.chipdocs.com/datasheets/datasheet-pdf/NEC-Electronics-Inc/RD10FB1.html
http://www.datasheetarchive.com/datasheet/pdf/17621.html
There seem to be data sheets on the second link as well.
The commercial number is:
1N4741 ---- 11V, 1 watt ..... but double check the data sheet.
Good work Goran ........ enjoy the new FIXED pedal.
Regards Dr. Bob
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Edited by - Dr. Bob on 05/10/2007 10:15:05 |
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Goran
Double Platinum Member
Sweden
2203 Posts |
Posted - 05/10/2007 : 09:24:40
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Thanks a lot again Dr Bob! What should we do without you!!
When fixed the DD-3 sounded just great, but the feeling of the successful removing of the zener, all the measuring, all the pain when no voltages was found and the happiness when it worked, that made it sound as the best delay I ever heard in my life.
I will print all the important stuff from this topic and keep it for further reference.
You should publish a book on pedal reapair Dr Bob!
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Goran
Double Platinum Member
Sweden
2203 Posts |
Posted - 05/11/2007 : 07:34:02
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Dr Bob aked for the story behind my broken DD-3, here it comes:
A friend of mine bought it on a forum type of site, got it tried it and it didn�t work. My friend usually never uses pedals, he plays in the style of Chet Atkins. But a delay seemed to him like a good idea�
He told me that he had been swindled (the seller said it worked when he posted the thing), as I collect Boss pedals I can trade the bad one for a working Ibanez TS-5 (the plastic bug)I said to him. He said yes as he wnated to try out an overdrive and a broken pedal is a broken pedal.
I was satisfied with a broken DD-3 as I already have a working DD-2 (identical inside).
Then I asked here at the forum and as you know I did fix it, with Dr Bobs help.
Yesterday I was at my friends home and told him that I had fixed it and asked what he had done with it from the start. He had not used a battery, he had used an adaptor. Show it to me, I said�. As you can guess it was a 9 V adaptor, but with the wrong polarity!!!! That really explain the burned the zener.
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Edited by - Goran on 05/11/2007 07:40:32 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 05/11/2007 : 08:56:01
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quote:
Originally posted by Goran
Dr Bob aked for the story behind my broken DD-3, here it comes:
A friend of mine bought it on a forum type of site, got it tried it and it didn�t work. My friend usually never uses pedals, he plays in the style of Chet Atkins. But a delay seemed to him like a good idea�
He told me that he had been swindled (the seller said it worked when he posted the thing), as I collect Boss pedals I can trade the bad one for a working Ibanez TS-5 (the plastic bug)I said to him. He said yes as he wnated to try out an overdrive and a broken pedal is a broken pedal.
I was satisfied with a broken DD-3 as I already have a working DD-2 (identical inside).
Then I asked here at the forum and as you know I did fix it, with Dr Bobs help.
Yesterday I was at my friends home and told him that I had fixed it and asked what he had done with it from the start. He had not used a battery, he had used an adaptor. Show it to me, I said�. As you can guess it was a 9 V adaptor, but with the wrong polarity!!!! That really explain the burned the zener.
Hi Goran
Thanks for filling us in.
it's a nice story, with a good outcome.
How did your friend feel, when you showed him, that it was his wrong polarity adapter, that caused the fault.
And not the seller lying to him.
I collect the SoundTank series 5 bug pedals as well.
I like them, that have almost identical schematics & parts, as in their bigger brother, series 10 pedals.
I like the CP5 compressor, & the DL5 digital delay, there is a memory mod for the DL5, to increase the delay time from 400mS to 800mS.
See the mod & tech forum, I did a writeup of how I repaired the DL5.
It's a few pages & months back.
Regards Dr. Bob .. |
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Craigory
Copper Member
Canada
3 Posts |
Posted - 02/17/2009 : 08:13:11
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Hey, I am having the exact same problem as Goran. I plugged in a podxt adapter unknowingly (apparently the wrong polarity) and the pedal started to smoke, and smell like burning electronics but i didn't notice it until about 15 seconds after i plugged it in :(. I removed the D6 zener diode. I have a dd3 third generation (the bottom pedal at the site comparing the different models of the DD3). A few questions:
1) Does anyone know if this was the right diode to remove from this model of the dd3? The pedal still doesn't work with the zener removed. I removed it by melting the solder around it.
2)Do I have to add more solder as it appears it looks like the circuit is incomplete where the zener diode was.
3) Is there anymore damage that could be done to the pedal other than just the zener diode blowing?
4) If i put in a 9V and press the switch the light doesn't turn on and no signal is passed through, but the battery will heat up. Is this an indication of anything?
Thanks for your help. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 02/17/2009 : 15:56:39
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Hi Craigory
Welcome to the forum from Australia.
I'm not 100% familiar with the later square SMD chip DD-3.
Regards Dr. Bob |
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Topic |
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Non working DD-3
