Source for Switch
I had opened up my Hafler DH200 to replace the on-off switch.
These switches have a short life span. I was able to find one that fits perfectly and is rated at 15 Amps 125VAC (the old was 10 Amps)
GC Electronics part number 35-689
It is more of a lighted rocker, rather than the original which was more of a toggle with a light. It was only about $5 (much cheaper than eBay)
I hope this is useful.
-Tom
I had opened up my Hafler DH200 to replace the on-off switch.
These switches have a short life span. I was able to find one that fits perfectly and is rated at 15 Amps 125VAC (the old was 10 Amps)
GC Electronics part number 35-689
It is more of a lighted rocker, rather than the original which was more of a toggle with a light. It was only about $5 (much cheaper than eBay)
I hope this is useful.
-Tom
Either:
http://www.allelectronics.com/cgi-bin/item/LRS-17/700225/120_VAC_LIGHTED_ROCKER_.html
or:
http://www.allelectronics.com/cgi-b...5/ON-OFF_LIGHTED_ROCKER_SWITCH,_120_VAC_.html
with:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=495-3056-ND
mounted from the switch to the fuseholder.
http://www.allelectronics.com/cgi-bin/item/LRS-17/700225/120_VAC_LIGHTED_ROCKER_.html
or:
http://www.allelectronics.com/cgi-b...5/ON-OFF_LIGHTED_ROCKER_SWITCH,_120_VAC_.html
with:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=495-3056-ND
mounted from the switch to the fuseholder.
Mouser has the exact replacement:
691-LTA201TRB/125N
And yes, they're now 15A, whereas the original part was 10A. The part was around $4 the last time I priced it; there's no need to pay that bozo on Ebay $15 if you can buy it for a third of that from Mouser.
The switch is a booger to replace unless you have fingers the size of toothpicks, but if it were easy you wouldn't be as appreciative once the job was done.
Grey
691-LTA201TRB/125N
And yes, they're now 15A, whereas the original part was 10A. The part was around $4 the last time I priced it; there's no need to pay that bozo on Ebay $15 if you can buy it for a third of that from Mouser.
The switch is a booger to replace unless you have fingers the size of toothpicks, but if it were easy you wouldn't be as appreciative once the job was done.
Grey
Hafler 220 Power Cord replacement
I own a Hafler 220 which I built from a kit 20 years ago.
This is sort of a newbie question, but I am in the process of replacing the Power cord. The original instructions say just to connect one end to the (TS) board and one to the (FC) fuse which leads to the power switch.
My replacement cord is the new standard with three wires - black (hot), white (neutral), and green (ground). I guess I will not be using the green wire, but which of the remaining wires go to the (FC) fuse connection?
Thanks
-Roger
I own a Hafler 220 which I built from a kit 20 years ago.
This is sort of a newbie question, but I am in the process of replacing the Power cord. The original instructions say just to connect one end to the (TS) board and one to the (FC) fuse which leads to the power switch.
My replacement cord is the new standard with three wires - black (hot), white (neutral), and green (ground). I guess I will not be using the green wire, but which of the remaining wires go to the (FC) fuse connection?
Thanks
-Roger
Black--aka hot--goes to the fuse. The idea is that if the amp dies, you don't want a bunch of electrons running loose in the amp so you stop them as soon as they enter the amp...not as they're about to exit.
(Yes, it sounds as though I'm describing DC instead of AC but the principle still holds...)
Grey
(Yes, it sounds as though I'm describing DC instead of AC but the principle still holds...)
Grey
The IRF parts are vertical MOSFETs, meaning that their Vgs will be something on the order of 4V or so. The Hitachi MOSFETs were lateral parts, which have a Vgs of 1 or 2V. As a result, the bias circuit needs to change or the MOSFETs will not bias. Other than that, you'll be okay, barring a bit of drilling and tapping to accept the new parts.
In addition, Nelson Pass has discovered that the P-ch IRF parts have an odd frequency-related gain problem. It is of minimal concern in a follower application (which this is), so it won't be much of a detraction, just something to be aware of.
Grey
In addition, Nelson Pass has discovered that the P-ch IRF parts have an odd frequency-related gain problem. It is of minimal concern in a follower application (which this is), so it won't be much of a detraction, just something to be aware of.
Grey
Hopefully most folks will conclude that the pinout is different when they get around to comparing the IRFP TO-247 case to the original metal can TO-3. That's why I mentioned drilling and tapping...the holes people drill for TO-3 devices are rarely oriented such that they give convenient mounting holes for TO-247s.
I think you'll find that the IRF MOSFETs are no worse than the Hitachis in terms of temperature stability.
Grey
I think you'll find that the IRF MOSFETs are no worse than the Hitachis in terms of temperature stability.
Grey
GRollins said:
1) Hitachi's discrete semi biz is now Renesas.
2) See Troy Huebner's application note at National Semiconductor on the temperature comp required for the Hexfets and LatFets. http://www.national.com/an/AN/AN-1645.pdf
3) The problem with securing the TO-247 device to a TO-3 surface area is that you don't want the surface area encountered by the TO-247 to be lessened by the Base Emitter holes of the TO-3. You just have to be a little careful in repurposing the heatsink for new devices.
jackinnj said:
1) Agreed, but the devices used in the Haflers are, and will remain as far as I know, out of production. With that in mind Renesas is irrelevant...it's not as though you can go to them for replacement MOSFETs. It's a pain when a part gets discontinued, but there's not much we can do about it.
3) Also agreed, but the Hafler heatsink has enough room on the flange to be workable. In our favor is the fact that the TO-247 case has an insulated mounting hole. The plastic around the hole shows clearly on the back. I don't mind that plastic not contacting metal if I can re-use a TO-3 mounting hole that will give me good placement for the MOSFET. If you have a relatively large, but still usable, hole but are concerned that the metal portions of the TO-247 might end up hanging over thin air, use one of those nylon insulators as a spacer to force the screw down the center of the hole. This will also center the plastic and the metal. Only use this trick if the hole is actually in a good position. I've got a dead Hafler that I'm going to be building a from-scratch circuit into when I have the time. Until I begin that project, I haven't got any specific advice as to whether any of the original Hafler holes are in a good position for mounting TO-247s. If all else fails, you can always mount to the main part of the heatsink and bypass the flanges entirely.
Grey
Hello all,
I was thinking of using the irfp transistors on a new heat sink either 2 or 3 pairs mounted on the heat sink to a daughter board
then using the PC19 driver boards with standoffs over the o/p
transistors to eliminate the long leads to the outputs. I bought the pc19 boards to put in my DH200 but now that i've sorted out the PC6 boards, I thought i would build something with some more real estate in the chassis (may be dual p/s) . Why have one amp when you can have two for twice the price???
any input is appreciated, Elwood
I was thinking of using the irfp transistors on a new heat sink either 2 or 3 pairs mounted on the heat sink to a daughter board
then using the PC19 driver boards with standoffs over the o/p
transistors to eliminate the long leads to the outputs. I bought the pc19 boards to put in my DH200 but now that i've sorted out the PC6 boards, I thought i would build something with some more real estate in the chassis (may be dual p/s) . Why have one amp when you can have two for twice the price???
any input is appreciated, Elwood
What is the attraction for using the vertical MOSFETs instead of laterals? Price?
I have used Exicon products as a drop in replacement for Hitachi MOSFETs in the TO-3 package with no problem what so ever.
FWIW, John Hillig at Musical Concepts claims the Exicons may be even a little better than the Hitachis.
I forgot the link to the Exicons, which I am sure most of you guys have:
http://www.profusionplc.com/pro/gex/prodGen.html?prdtyp=lateral mosfet
Dick
http://www.profusionplc.com/pro/gex/prodGen.html?prdtyp=lateral mosfet
Dick
I swear I thought I'd put a post in this thread last night, but my computer was screwing up and apparently it didn't work. Time to stick more pins in my Bill Gates voodoo doll.
Aside from the fact that the price is at least four times (often more) that of verticals, lateral MOSFETs are hard to get in the US.
As for the basic idea of using the Hafler front end to drive IRF outputs...go for it. Pick a target power, decide how hard you want to bias the output stage, then start hunting a power transformer and heatsinks. Those two will be your limiting factors. As always.
Grey
Aside from the fact that the price is at least four times (often more) that of verticals, lateral MOSFETs are hard to get in the US.
As for the basic idea of using the Hafler front end to drive IRF outputs...go for it. Pick a target power, decide how hard you want to bias the output stage, then start hunting a power transformer and heatsinks. Those two will be your limiting factors. As always.
Grey
The irf devices may be subject to thermal run away tending to
draw more current as they get warm ect. The lateral mosfets
tend to draw less as they get hot.
I would like to know the thermal specifications of the dh200
heat sink. Has some one got that figure?
I picked up a used DH200 in bad shape broken fuse holders
bent case and some cut wires. And it appears that it had been
bridged using a small ~2" square PC-7 board for some reason
it looks like this board was being uninstalled when I got it wires
cut ect. This is ALL I know about this module other than I don't
need it at all. Free to the first person that NEEDS it. Picture?
well for free you don't get picture, pictures are $10 extra in advance. If no one takes it by 3-25-08 consider this offer dead.
draw more current as they get warm ect. The lateral mosfets
tend to draw less as they get hot.
I would like to know the thermal specifications of the dh200
heat sink. Has some one got that figure?
I picked up a used DH200 in bad shape broken fuse holders
bent case and some cut wires. And it appears that it had been
bridged using a small ~2" square PC-7 board for some reason
it looks like this board was being uninstalled when I got it wires
cut ect. This is ALL I know about this module other than I don't
need it at all. Free to the first person that NEEDS it. Picture?
well for free you don't get picture, pictures are $10 extra in advance. If no one takes it by 3-25-08 consider this offer dead.