Repair/rejuvenation of Insteon 2413U PLM and 2450 I/O Linc

If you’ve found this post, it may be that you have an unhappy Insteon 2413U Power Line Modem as part of your Indigo system, and are wondering if it can be brought back to life. As is well known by most Insteon users, SmartHome has faded to black, and finding replacement Insteon gear is getting harder and harder.
Although -- late-breaking news -- PLMs may be reappearing on the market next month per this announcement: “Product arriving April 2023”.
https://shop.insteon.com/en-ca/products ... -interface.

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Update (Dec 2023) - SmartHome/Insteon has returned from the dead. The 2413U USB PLM is available here (in Canada), and presumably elsewhere.
https://www.aartech.ca/2413u/insteon-po ... modem.html
Since replacing the capacitors in my 2413 and 2450 several months ago, both have been working fine.
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I’ve been using Indigo + Insteon for nearly a decade and would rather not abandon the Insteon investment if I can wring a few more years of life out of my 2413U. It’s version V1.C, date code 1426 (i.e., manufactured week 26 of 2014). There are lots of articles posted online about how to replace the electrolytic capacitors which are a frequent failure mode with the product. The most useful resources that I found are linked below. They are quite dated, and the essential information (what replacement capacitors to purchase) is mostly obsolete.

For the benefit of anyone considering “re-capping” their PLM, here is the list of capacitors I used. They were available from DigiKey.com, as of March 2023. All are from Nichicon (a well-regarded maker of quality caps) except for C2, 5 & 8 which are from Würth. I chose components with the longest rated lifetime running at 105C, available at reasonable cost.

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C3        6.8uF @ 350V     UCS2V6R8MPD            10000hrs @ 105C
C7 & 13   100 @ 35V        UPV1V101MGD1TD         5000hrs @ 105C
C11       100 @ 50V        UPJ1H101MPD6TD         5000hrs @ 105C
C8        10 @ 16V         860160372001           4000hrs @ 105C
C2 & 5   same as C8   

Total cost for the 7 capacitors was $5.14 CAD. Shipping was $8. The order was delivered by FedEx a mere 23 hours after I placed it at digikey.ca!

Notes
C3 filters the output from the primary full-wave rectifier which sits directly across the 120VAC mains supply. The output is 170 VDC nominal. Original Insteon design used 6.8uF @ 250V. Given the voltages involved and the possibly of spikes on the AC supply, a higher rated cap is indicated, hence the 350V component for replacement. I tried a 10uF @ 400, but it was too big to fit.

C7 & C13 are part of a “Pi-filter” which sits at the output of a DC-to-DC converter (170 VDC in, 22 VDC out). The original design of the 2413 apparently used 10uF @ 35V. Later revisions beefed up these two components to 100uF @ 35V. Some posts suggested replacing these with caps rated for 50V to provide a little more headroom, but I found they were too big to fit on the PCB so I chose 100 @ 35, the same as the original design The DC-to-DC converter runs at 200 KHz - hence a fair bit of high-frequency noise is present. The use of capacitors with low ESR is preferred to attenuate the noise. (If you’re an EE, you’ll know what ESR means. If not, don’t worry about it).

C11 is at the output of the 5 VDC regulator. The original design used 100uF @ 25V. I used 100 @ 50V, since I had one on hand, and it fit on the PCB. You could also use 100 @ 25V (UHV1E101MED), or 100 @ 35 (UPV1V101MGD1TD).

C8 is an unremarkable 10uF @ 16V.
C2 & C5 are on the daughter board which comprises the USB interface. I had no reason to think these two were bad, but since I had the 2413 disassembled, I decided I’d replace all the electrolytics while I had it apart.

References
A valuable source of information about repairing the PLM is a 29-page series of posts that was started in Aug 2014 on the Universal Devices forum. It was active until April 2022, and then was closed for further input.
https://forum.universal-devices.com/top ... ply-fails/

It focuses on the 2413S variant of the PLM, which has a serial interface to the host computer. As it turns out, the USB version of the PLM (2413U) has the same main PCB design, comprising the power supply, the power line modem (22 MHz), and the RF transceiver (914 MHz). Different daughter boards then provide different types of connection to the host computer.

Another good resource is this one:
https://1projectaweek.com/blog/2017/6/2 ... -plm-2413u

As is this one, which also focuses on the 2413U version of the PLM.
https://www.rototron.info/insteon-plm-repair-tutorial/

The author of the rototron tutorial above also posted an excellent Youtube video showing the complete repair job from start to finish.
Highly recommended if you’re contemplating this DIY electronics project.
https://youtu.be/Ab0tW7vgP1I

As part of my Insteon rejuvenation project, I also recapped my 2450 I/O Link. Fortunately, it has a similar (though not identical) power supply design. I’ll put up another post here with details of the components I used for it and a couple of issues I encountered.

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As noted in my previous post, the PCB in the 2450 is similar, though not identical, to that in the 2413. The power supply design is similar (3 stages) and the labeling of the electrolytic capacitors is the same. My 2450 (V2.4, manufactured week 42 of 2016) seemed to be working OK, but I decided to replace all the capacitors as part of my ‘rejuvenate Insteon’ project.

Here’s the list of parts I used, all in stock at Digi-Key as of March 2023.

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C3      6.8uF @ 350V      UCS2V6R8MPD        10000hrs @ 105C
C7      100 @ 50V         UPJ1H101MPD6TD      5000hrs @ 105C
C11     100 @ 35V         UPV1V101MGD1TD      5000hrs @ 105C
C8      10 @ 16V          860160372001        4000hrs @ 105C

A useful article about the 2450 is here:
https://forum.universal-devices.com/top ... revisions/

Notes:
C11 - The original component in my 2450 was a 100@50V. I had a 100 @ 50V on hand, but it was too big to fit, so I used one rated at 35V.
According to the linked article above, previous versions of the 2450 (V1.0, V1.8, V2.3) all used a 25V cap for C11. From what I can tell, the cap sits on the output of the 5V regulator, so the rating of the original component (25V) should be fine. The 35V replacement I used should be more than fine. I don’t know why Insteon would have used a 50V component in my V2.4 2450. Perhaps they ran out of 25V components the week mine was built and swapped in a 50V.

C7 - This is where the 2450 design deviates from the 2413. The latter employs a Pi filter at the output of the switching regulator, comprising C7, C13, and L1. For details on the Pi filter, look here: https://youtu.be/Ab0tW7vgP1I?t=333

The 2450 did away with C13 and L1 (I.e., no Pi filter). On my V2.4 hardware, C7 was 100uF @ 50V, mounted horizontally, cantilevered over surface-mount components on the PCB. In addition, Insteon added a 2nd capacitor in parallel with C7. It’s an SMCC (surface mount ceramic capacitor) whose purpose is get better attenuation of the high-frequency noise coming out of the 200 KHz DC-to-DC converter. The SMCC is teeny-tiny - it’s soldered directly to the PCB between the two leads of the 100/50 electrolytic.

To replace C7, I did not want to disturb the SMCC. So instead of unsoldering and removing C7, I cut its leads, leaving about 1/2” protruding up from the PCB. Then carefully soldered the replacement to the stubs. I also changed the orientation from horizontal to vertical. The size of the replacement was such that the top — which is uninsulated — would have been extremely close to the body of the push-button switch (which is grounded). To avoid the possibility of a short between the two, I mounted C7 in a vertical orientation, cantilevered above a couple of components on the PCB, and secured with a dollop of epoxy.

After replacing the 4 capacitors, I reassembled the 2450 and put it back in service. Hopefully, I’ll get several more years out of it.

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