Dbx 266XL transformer dead
- Thread starter biquet82
- Start date
ranjam
New member
My own experience with dbx (or Harmon) is that they are just gawd-awful about even admitting who they are, never mind releasing parts or schematics to the great unwashed who are unfortunate enough to own anything dbx (or any other Harmon product). No, you send the unit to them, and only they have the Lourdes water needed to resurrect your compressor. End of rant.
I cheat on electronics repairs all the time. The last dbx compressor I opened up, and your should be similar, will have clues all over. If you see something like an LM7815 and/or a LM7915, you have a +15VDC supply. Look at the filter capacitors right around the regulator(s). It may have a positive and a negative supply, so be careful. But if the filters are 25VDC, it likely is a 15-volt supply.
A possible schematic looks like this;
anything that can supply maybe 500mA should work, but obviously you'll look at the physical size of your replacement transformer and be sure it can fit inside the unit.
I cheat on electronics repairs all the time. The last dbx compressor I opened up, and your should be similar, will have clues all over. If you see something like an LM7815 and/or a LM7915, you have a +15VDC supply. Look at the filter capacitors right around the regulator(s). It may have a positive and a negative supply, so be careful. But if the filters are 25VDC, it likely is a 15-volt supply.
A possible schematic looks like this;
Thank you for your reply.
I live in France, and I bought this DBX to a french guy a few years ago, with a 220V/120V adapter.
Please see this picture:
We can see "PWR1 +15" near the right transistor, and "PWR2 -15" near the 7915 on the left (I'm sure it's 7915 on the left; but the right one.. I can't open the metallic cap).
Capacitor are 16V and 35V (two big)
What do you think? Like me, +-15VDC?
What is specs for the replacement transformer: 120V/15V 60hz? So where can I find one?
Thank you
I live in France, and I bought this DBX to a french guy a few years ago, with a 220V/120V adapter.
Please see this picture:
We can see "PWR1 +15" near the right transistor, and "PWR2 -15" near the 7915 on the left (I'm sure it's 7915 on the left; but the right one.. I can't open the metallic cap).
Capacitor are 16V and 35V (two big)
What do you think? Like me, +-15VDC?
What is specs for the replacement transformer: 120V/15V 60hz? So where can I find one?
Thank you
ranjam
New member
Yeah, that looks familiar, and it's as I suspected. Nothing too complicated. It's a +15VDC power supply. Where to get a transformer is the problem. The 35VDC capacitor is probably just what they had a warehouse full of. No, wait. The 35VDC caps are the input and the 16VDC caps are the output. But they look OK, although check the +15VDC one to see if that bulge on top is my imagination. If that 'X' pattern on the 35VDC caps looks like it's bulging, change all those caps too.
This is where Google or another forum member has to help. Unless Digikey or someone similar has a European warehouse, you want to find a more local supplier. But the specs ought to be 120V/15V 60Hz at maybe 500mA or even a little less. Something that will physically fit inside the unit. You'll likely have to drill some new mounting holes, but that is usually a given.
This is where Google or another forum member has to help. Unless Digikey or someone similar has a European warehouse, you want to find a more local supplier. But the specs ought to be 120V/15V 60Hz at maybe 500mA or even a little less. Something that will physically fit inside the unit. You'll likely have to drill some new mounting holes, but that is usually a given.
ranjam
New member
I would think as long as the transformer fits, anything goes. The power supply doesn't care how it sees 15VAC, all it cares is that it does see 15VAC. All I can see is the ratio; 115VAC to 15VAC is a little less than 8:1 and 220VAC to 15VAC is a little less than 16:1 so the core is actually smaller. However, the 50Hz line frequency means more iron to get the inductance up there, so it may go back to being bigger. It may average out to being the same size.
I'd look at the physical size, and use whatever works 'best', meaning as little drilling or cutting the dbx chassis to make it fit.
I'd look at the physical size, and use whatever works 'best', meaning as little drilling or cutting the dbx chassis to make it fit.
dbx 266XL power problem
I am having the same issue.
Here's what my the power transformer reads.
Billion
26-0245-a
E2-416TF-SS1-0057
It just fails to power on. I can not see anything inside that shows something may be wrong, like bulging capacitors. Anyone have any experience repairing these? I took a photo of the power transformer. Should I attempt to replace it?
I am having the same issue.
Here's what my the power transformer reads.
Billion
26-0245-a
E2-416TF-SS1-0057
It just fails to power on. I can not see anything inside that shows something may be wrong, like bulging capacitors. Anyone have any experience repairing these? I took a photo of the power transformer. Should I attempt to replace it?
PRHunt
I void warranties
If there is no fuse receptacle on the back of the unit, then it is probably on the circuit board close by the power transformer. With the unit completely unplugged from power, open the enclosure and have a look. Post a *clear* photo if you are not sure about what you see.
PRHunt
I void warranties
no, those metal pieces are heatsinks for the voltage regulator devices. I would expect the fuse to be near the power transformer. There should be a fuse somewhere between the power input receptacle and the transformer. Can you get a pic of the power input area of the unit, including the transformer?
I am wondering, though, if you should really be getting a tech to check the unit for you. For someone with appropriate knowledge, it should be quite simple to troubleshoot. It can also be very dangerous for someone without that knowledge.
I am wondering, though, if you should really be getting a tech to check the unit for you. For someone with appropriate knowledge, it should be quite simple to troubleshoot. It can also be very dangerous for someone without that knowledge.
ranjam
New member
Wow. Three years later and I get to answer again! What I might do, and this is just a crazy idea, is to mount an AC adapter jack on the chassis, and use whatever AC adapter you need. If you need 120/15, you use it. If you need 220/15, use that. As long as you use an AC adapter. Maybe 500mA or 1A is all you'd need. That's how my 266 is powered, so it should work just fine.
PRHunt
I void warranties
Well, I did a little bit of reading, and it is possible that the transformer has an integral fuse.
If it was my gear, I'd probably just stick in an off-the-shelf transformer - maybe 15-20VA with 15-0-15 secondaries - and install a fuse holder. Don't know how much space is inside though, and it would help to have a schematic.
I did also read a post somewhere suggesting that DBX might sell a replacement transformer directly.
Paul
If it was my gear, I'd probably just stick in an off-the-shelf transformer - maybe 15-20VA with 15-0-15 secondaries - and install a fuse holder. Don't know how much space is inside though, and it would help to have a schematic.
I did also read a post somewhere suggesting that DBX might sell a replacement transformer directly.
Paul
PRHunt
I void warranties
Aracaxis, could you grab a voltmeter and check the board voltage from the regulators?
I'd have thought that 21.9V secondaries on the transformer would be on the high side for a regulated 15V. The earlier shots from the 266XL would seem to indicate that it runs from + and - 15V?
It also looks like the transformer is always powered - that is, I see no switching on the transformer primaries.
Paul
I'd have thought that 21.9V secondaries on the transformer would be on the high side for a regulated 15V. The earlier shots from the 266XL would seem to indicate that it runs from + and - 15V?
It also looks like the transformer is always powered - that is, I see no switching on the transformer primaries.
Paul
Will this work?
I have only used this to test audio cables. I have zero experience with testing power transformers. I'm willing to follow careful instructions! I don't want to take this to a tech because it's cheap & not important to my set up. Thank you for being patient with me.
I have only used this to test audio cables. I have zero experience with testing power transformers. I'm willing to follow careful instructions! I don't want to take this to a tech because it's cheap & not important to my set up. Thank you for being patient with me.