zee
Junior Member
Posts: 75
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Post by zee on Oct 9, 2006 19:21:20 GMT -5
Had to do something...
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Post by jsaily on Oct 10, 2006 14:27:44 GMT -5
The LDO regulator we included in the 1541-III-DTV kits would no doubt do fine ;-) It should output 800mA no problems if heatsinked.
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zee
Junior Member
Posts: 75
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Post by zee on Oct 10, 2006 15:49:04 GMT -5
I also have several in storage waiting. Trying to figure out the best location to put one on the board without using any jumperwires, to make it neat.
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Post by gmoon on Oct 10, 2006 19:49:56 GMT -5
Have you checked the power consumption with the on-board regulator removed? (I.E. powered up with an external regulator.)
If so, could you give us the current draw before you install the LDO?
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zee
Junior Member
Posts: 75
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Post by zee on Oct 11, 2006 1:25:40 GMT -5
Not yet but I'll keep that in mind.
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zee
Junior Member
Posts: 75
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Post by zee on Oct 14, 2006 8:27:39 GMT -5
Hmm, normal DTV doesn't seem to be that powerhungry. Only about 166mA with it's original regulator design.
Now with Q1, R2, R6, R8, R9 & LED removed using external supply the board without regulator draws only 99mA.
After using the 3.3V LDO regulator the current drawn is 140mA.
Also the amount drawn seems to change after power off and on again. Sometimes with separate PSU it was 99mA and at another moment it was 115mA. Now with the LDO it's usually at 140mA but at another start it was drawing only 125mA.
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Post by MadModder on Oct 14, 2006 8:50:11 GMT -5
I forgot to meassure the current without any regulator, sorry... Anyway, I removed Q1, R2, R8 and R9. That is enough. I left R6 so the LED would light up. madmodders.se/temp/C64DTV/33VLDO.jpgThe glue is Arctic Silver Thermal Adhessive. First I thought about super glue, but that doesn't hold for much heat, so I thought why not use thermally conductive epoxy? Now the whole thing (with 1541-III-DTV) draws 245mA.
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Post by gmoon on Oct 15, 2006 15:17:33 GMT -5
Thanks for all the info, guys.
There does seem to be some inherent differences between the PAL DTV2/3 and the Hummer. Hummer usually draws about 140 mA (stock regulator w/LED) a not-insignificant amount less than the 165+ you're finding.
At least once when I had another device tapped from the board through a diode, it seemed to drop the voltage from the onboard regulator and the board and uC together only drew 130 mA! (the video was darker than usual, but everything still functioned..)
I am a little surprised that the LDO by itself consumes 40mA.
Also, there is some change in power consumption when using IEC devices, like a real 1541 (the OC inputs will sink 3-4 mA more.)
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zee
Junior Member
Posts: 75
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Post by zee on Oct 15, 2006 15:58:35 GMT -5
This is the current state of my board. Several parts removed, few rewired/swapped so it takes as little space as possible when placed underside the keyboard and the 3.3V regulator nicely in place. oms.wmhost.com/dtv/dtvdcr.jpg - Before oms.wmhost.com/dtv/dtvldo.jpg - After The red line to the right of the regulator is where I had to cut the goundplate so it possibly couldn't shortcircuit the regulator. Also the capacitor C31 is moved to the place of C8. R1 had to be removed too, but since I don't have the Dis-line connected at all it doesn't matter at the moment.
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