Modify HMv4.0 to support a damper


 
R

RRiedesel

New member
The HMv4.0 has served me well the last couple of years and I've just started exploring adding a damper for some additional control. It looks like there are a couple approaches for wiring but the cleanest would be to update the blower driver circuit to 4.1 based on this thread and add a cat 5 jack:

http://tvwbb.com/showthread.php?50543-HMv4-0-to-HMv4-1/page3&highlight=4.0+blower+circuit

Are there any downsides to this approach? Any other feedback from those who have done the mod and used it long term?
 
You only need to update the blower circuit if you want to share the ground between the servo and the blower and make the CAT5 jack pinout compatible with the standard pinout used today. For a one-off unit you could use the spare pins on the CAT5 jack to power the blower with the existing circuit.
That said, I would agree with the upgrade of the blower circuit and also suggest you add the RC filters to your HMv4.0 as this is a huge improvement in probe stability. I have done both of these upgrades to my HMv4.0 and it is a solid unit.
 
FYI, I started that thread detailing how I converted my HMv4.0 blower circuit to the HMv4.1 blower circuit, but after the HMv4.2 was released I also added details on how to upgrade HMv4.0 to HMv4.2 blower circuit. You can find that info in post 19 here.

If you are going to upgrade your HMv4.0 blower circuit you might as well update to v4.2, this way you will be able to use Voltage Mode for the blower and will have the circuit being used on the current release... and again, add the RC filters, big improvement, that mod is detailed in that thread as well...
 
As you can see my name is all over that thread as I upgraded my 4.0 to a 4.2 using Ralph's directions. I can attest that everything works flawlessly and gives new life to the 4.0.
 
Thanks for the feedback and pointing me to do the full 4.2 upgrade. I'll pull together a component list and get the parts on order!
 
Here is a list of the components needed in case anyone else wants to do this upgrade. Mouser project link https://www.mouser.com/ProjectManager/ProjectDetail.aspx?State=EDIT&ProjectGUID=47A658EE-03E5-4F0B-B692-6F3F37C9A2D7

And components in case that doesn't work:

HeaterMeter 4.0 to 4.2
Mouser # Mfr. # Manufacturer Desc. RoHS Lifecycle Customer Part # Order Qty. Price (USD) Ext.: (USD)
291-100K-RC 291-100K-RC Xicon Carbon Film Resistors - Through Hole 100Kohms 0.05 RoHS Compliant 5 $0.10 $0.50
291-68K-RC 291-68K-RC Xicon Carbon Film Resistors - Through Hole 68Kohms 0.05 RoHS Compliant 1 $0.10 $0.10
291-22K-RC 291-22K-RC Xicon Carbon Film Resistors - Through Hole 22Kohms 0.05 RoHS Compliant 1 $0.10 $0.10
291-2.2K-RC 291-2.2K-RC Xicon Carbon Film Resistors - Through Hole 2.2Kohms 0.05 RoHS Compliant 2 $0.10 $0.20
594-K104K15X7RF53L2 K104K15X7RF53L2 Vishay Multilayer Ceramic Capacitors MLCC - Leaded 0.1uF 50volts 10% X7R 2.5mm LS RoHS Compliant By Exemption 4 $0.10 $0.40
511-1N5819 1N5819 STMicroelectronics Schottky Diodes & Rectifiers Vr/40V Io/1A BULK RoHS Compliant 1 $0.41 $0.41
512-BS170 BS170 Fairchild Semiconductor MOSFET N-Channel MOSFET RoHS Compliant 1 $0.39 $0.39
512-FQU11P06TU FQU11P06TU Fairchild Semiconductor MOSFET 60V P-Channel QFET RoHS Compliant By Exemption 1 $0.87 $0.87
652-RLB9012-221KL RLB9012-221KL Bourns Fixed Inductors 220uH 10% 1A RoHS Compliant 1 $0.58 $0.58
647-UPW1E470MDD UPW1E470MDD Nichicon Aluminum Electrolytic Capacitors - Leaded 25volts 47uF 5x11 20% 2LS RoHS Compliant 1 $0.16 $0.16
523-RJHSE-5080 RJHSE-5080 Amphenol Modular Connectors / Ethernet Connectors R/A RJ45 NONSHIELDED 8 CONT NO LEDS RoHS Compliant 1 $0.91 $0.91
 
I'm wondering how you are gonna deal with that pc mount RJ45 jack without a circuit board to go into? I used the keystone style jack that you punch wire down into, and cut a slot in the case for it to fit. I glued down a couple pieces of the case I cut out to grab the latch and hold it in place, worked like a charm, went easier than I had expected...
 
When I saw the jack on the parts list for 4.2 I thought I would just order it since it was cheap not realizing the connection type. Looks like I'll use one of the punch down jacks I have laying around and put that one in the spare parts bin.
 
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