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UNLEADED
Copper Member
Canada
10 Posts |
 Posted - 10/28/2009 : 11:35:17
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Hello fellow members,
I need your help with this:
Just bought a Boss OD-1 with batch number 8200(May 1979?!).
It does have a 14 pins/legs chip but it is not the RC3403ADB.
It has a XR430AW(LM324N) OP-AMP chip instead.Is this chip OK or has nothing to do in this pedal.
I am not an expert and it is hard for me to tell if this chip is original from Boss of that period or a replacement chip.
I can post close up pics of the chip if needed.
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Edited by - Dr. Bob on 10/28/2009 15:05:21 |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 10/28/2009 : 11:45:27
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Pictures would definitely be helpful. Preferable from both the component and the solder side of the board.
8200 would normally have the RC3403ADB but it's quite close to the time when it was replaced with the uPC4741 chip so it is possible that they experimented with other chips too (although unlikely). |
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verivorax
Platinum Member
Canada
1185 Posts |
Posted - 10/28/2009 : 12:06:40
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I'm definitely interested in seeing this as well.. I'd like to see if this oddball op-amp is original or replacement. Great find on the OD-1!  |
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UNLEADED
Copper Member
Canada
10 Posts |
Posted - 10/28/2009 : 12:30:01
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quote:
Originally posted by UNLEADED
Hello fellow members,
I need your help with this:
Just bought a Boss OD-1 with batch number 8200(May 1979?!).
It does have a 14 pins/legs chip but it is not the RC3403ADB.
It has a XR430AW(LM324N) OP-AMP chip instead.Is this chip OK or has nothing to do in this pedal.
I am not an expert and it is hard for me to tell if this chip is original from Boss of that period or a replacement chip.
I can post close up pics of the chip if needed.
I am not very good with computer stuff.Last time I posted some pics I was told they where too big in size and I dont know how to reduce the size before sending them.Here is some pics anyway...
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Original Hi-res file/s respectfully left untouched, new re-sized file name/s:
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100_4321s.jpg
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Edited by - Dr. Bob on 10/28/2009 15:04:21 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/28/2009 : 13:47:37
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Looking at the picture of the solder side, it appears to me that the chip has been changed - the solder flux marks are different around the chip.
I'd guess the original chip was broken somehow (probably reverse voltage) and a tech has done a replacement.
Assuming that is actually the case, to put it back to original, you will need the 3403 chip. You can get an equivalent here:
http://www.vintageplanet.nl/semiconductors.html
To get an original period part, the only real way is to harvest one from and old piece of gear. If i ever need one myself, my plan is to buy a PH-1 pedal and swap the 3403 chip in it for a TL074 (the tone of a phaser is less dependent on the opamp).
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 10/28/2009 : 15:16:19
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Hi UNLEADED, Bossarea, Laurie & Guys
There also appears to have been some re-wiring/rework done,
around the blue wire in the first picture.
(top right just above Connection 14).
And if the opamp was replaced due to something like reversed voltage?
The protection diode would also have been changed.
Perhaps the guys with OD-1A's can verify if this is the case, with both changes/repairs.
I guess I mean (Laurie) when I say guys.
UNLEADED can I ask what country you are from?
It's not in your profile.
I sometimes (find) vintage 3403's & other goodies, in some of the consumer equipment that finds it's way to my humble Lab.
The equipment usually ends up being disassembled for it's valued, vintage & difficult to get parts.
Regards Dr. Bob 
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Edited by - Dr. Bob on 10/28/2009 15:19:28 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/28/2009 : 15:24:14
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quote:
Originally posted by Dr. Bob
Hi UNLEADED, Bossarea, Laurie & Guys
There also appears to have been some re-wiring/rework done,
around the blue wire in the first picture.
(top right just above Connection 14).
And if the opamp was replaced due to something like reversed voltage?
The protection diode would also have been changed.
Perhaps the guys with OD-1A's can verify if this is the case, with both changes/repairs.
I guess I mean (Laurie) when I say guys.
UNLEADED can I ask what country you are from?
It's not in your profile.
I sometimes (find) vintage 3403's & other goodies, in some of the consumer equipment that finds it's way to my humble Lab.
The equipment usually ends up being disassembled for it's valued, vintage & difficult to get parts.
Regards Dr. Bob
Yeah, 12 and 13 have definitely been reterminated. Interesting to see bare copper there though.
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UNLEADED
Copper Member
Canada
10 Posts |
Posted - 10/28/2009 : 15:59:56
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Thanks for the feedback.
I am aware of the blue wire being resoldered and I will take care of that.
But what about the XR430Aw chip in there.Is it period correct from an obscur manufacturer and does it (or not) belong in there at all.
Since this is the only OD-1 I own I cannot compare(A/B test)to an original from the same period.
The pedal sounds pretty good to me but I would absolutely be a buyer for the correct chip.
BTW,I am from Quebec,Canada. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/28/2009 : 16:26:56
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quote:
Originally posted by UNLEADED
Thanks for the feedback.
I am aware of the blue wire being resoldered and I will take care of that.
But what about the XR430Aw chip in there.Is it period correct from an obscur manufacturer and does it (or not) belong in there at all.
Since this is the only OD-1 I own I cannot compare(A/B test)to an original from the same period.
The pedal sounds pretty good to me but I would absolutely be a buyer for the correct chip.
BTW,I am from Quebec,Canada.
Please see my first post in this thread. |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 10/28/2009 : 21:27:06
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It's the second line of text on the chip that's the type so it's really a LM324N. You can find the datasheet from one of the links on this page: http://www.datasheetcatalog.com/datasheets_pdf/L/M/3/2/LM324N.shtml
The logo indicates that your chip is made by National Semiconductor.
Don't know what the XR number mean. |
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UNLEADED
Copper Member
Canada
10 Posts |
Posted - 11/03/2009 : 23:21:43
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I took a close look at the solders of the actual LM324N chip and it looks to me like they are original(untouched).If someone replaced that part,they did a pro soldering job 'cause there is not a trace of solder left on the board(PCB).
My guess is what we see is some glue residue (instead of flux residue) from the little square foam pad that was glued on the board?!
Question:Is it true that some early PH-1 Phaser were also equiped with a LM324N oP Amp chip?!
I read that on another thread about the PH-1 pedal from this site.
It may explain the hole thing about the LM324N being there in my 1979 OD-1 instead of the RC3403ADB.
Anyways,my OD-1 sounds great and I will leave it this way for now.
Thanks laurie,Dr.Bob, and everyone else from this site.
I know I can count on you guys! |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 11/04/2009 : 15:34:47
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Hi UNLEADED
I didn't reply to this right away, as I seem to remember
seeing at least one OD-1 that used the 14 PIN - UPC474 (quad LM741) opamp.
I searched around my (Hmmm well sorted ) collection of Boss pics
and I did find one pic,
of an OD-1 with the UPC474, slightly obscured by a brown wire,
but if you zoom in - you will see the UPC474 marking on the IC.
So I'm not surprised that there may be a some OD-1's with LM324 opamps in them.
In the background top left .
You can see the Clear Skeleton switch & a rusty SS Silver Screw.
Regards Dr. Bob |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 11/04/2009 : 16:37:19
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I looked again at the hi-res pic of the track side of the board, and I stand by my assessment that the IC has been resoldered. The flux flow around the pins of the chip and the transistor pads to the right of the IC just seems to be different to my eye to all the rest of the board.
My money remains on the IC and that transistor having been changed at some point. |
Edited by - Laurie on 11/04/2009 16:42:52 |
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 11/04/2009 : 17:07:57
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| The LM324 contains four 741 opamps with the offset compensation pins removed. Another peculiarity is that this chip is designed to be operated from a single power supply between 0-30V. In my experience it sounds decent in audio applications, so if it was me I'd leave it in my OD-1. It doesn't look like the original but it probably should sound as good. |
Edited by - cctsim on 11/04/2009 17:08:47 |
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verivorax
Platinum Member
Canada
1185 Posts |
Posted - 11/05/2009 : 02:00:54
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The pic of my OD-1 #8700 is here: http://bossarea.com/forum/topic.asp?TOPIC_ID=4147&whichpage=15, IC unobscured.
In my non-professional opinion, If I were evaluating the pedal for originality, I would definitely conclude that it had been re-soldered as well. If the excess code on the IC can reveal a date code.. it might help. At any rate, if the IC is original, then it's definitely an anomaly. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 11/05/2009 : 02:11:38
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quote:
Originally posted by verivorax
In my non-professional opinion, If I were evaluating the pedal for originality, I would definitely conclude that it had been re-soldered as well.
Here is my OD-1. Definitely does not show the same solder marks.
On mine, you can see solder is the same over the whole board...
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Topic |
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Boss OD-1 OP-Amp chip
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