This is based on the Motorola EB104 bulletin:
- EB104 amplifier board ordered from Communications Concepts, including 4x MRF150
- Omron 12V Relays ordered from Ebay – used for TR switching and filter selection
- Toroids and accessories orderd from Amidon
- Large heatsink gotten from my father, TF3T
- 1200VA toroid transformer was bought in my trip to Shanghai – loong story there!
- Going to order some silver-dipped MICA capacitors and PIC MCU + filter capacitors from www.mouser.com
Still need:
- Copper spreader
- 12v cooling fans
- Hardware
- Heatsink for the PSU – asking locally
Next thing is to build the case
Going to build it from Aluminium parts available locally, have made some sketches in AutoCad, but it’s hard to draw it exactly as I don’t have all the components in hand, and don’t know the exact dimensions of some of the components.
“Heatsink for the PSU.” Hmmmm
Hefur þú hugsað út í hvað það myndi einfalda allt ef
þú slepptir því að regulera spennugjafann.
Eg hef séð að fyrir þennan magnara sé góð spenna 44-47VDC, þ.e.a.s.
fyrir minnst IMD. Slíkur spennir væri þá væntanlega ca. 35VAC með afriðli,
þéttum og álagsviðnámi að gefa þér rétta spennu en án þeirrar hitamyndunar
og vandamálum sem fylgja reguleringu re. (Heatsink for the PSU) og yfirspennuvörn.
73 de TF3G
Ben,
When you get the board and set the mounting holes for the board and the transistors, I would like to know the location of the holes on the copper spreader. I am going to lay out a new PCB for different devices but I want the holes to line up so the new board will fit on spreaders made for the EB104. The printed artwork is “not to scale”.
I make transistors that are compatible with MRF150 circuits but are a more rugged design. If you are interested in trying some let me know.
thanks,
Dick
OK, my mistake, I thought this was a progress report in Icelandic.
What I was suggesting was to use an unregulated PSU for this Amp.
Regulating a PSU, of this size, with many bipolar transistors, is scary
in my opinion.
TF3G
yee..I decided to have this site in english, try to add to this EB104 forum that is on “google”. I understand the non-regulated regulated thing..
I have a 1200VA transformer now, I’m going to use that as I don’t have any other 1000-1200VA around.. So better use what I have.. secondary is to high, around 55v.
It is scary – I might see if it’s easy to unwind some of the windings on the transformer – that could be a possibility.
Plan is then to add another 600W EB104, then I might look into using a switch mode supply. So if anyone has a good design for me, please share.
I will drill the copper spreader tomorrow, will post a picture with scale. Just broke my only working 2mm drill…so as I’m sick, my brother bought some new drills !
Nice pics Benni.
As for the transformer. 55Vac will give you 77Vdc. You will definately need to
remove some of the secondary windings. For instance, 40Vac will give you 56Vdc,
and if you regulate that down to 48Vdc (?) means quite a lot of heat that you need to remove.
Anyway, a very interesting project.
TF3G
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