| Author | Message | ||
     Edward Mckinley New User Username: ed_mckinley Post Number: 10 Registered: 10-2019 |
Wondering if anyone would happen to know the replacement microrelays found on the HVAC control board. In trying to rectify intermittent heating, I believe I have narrowed my search down to the board being the culprit. I would like to replace the failed components myself as it appears to be a fairly simple single layer circuit board. Mr. Treacy mentioned years ago of a fujitsu replacement for the microrelays but the part numbers show up as "obsolete" in my search. Thanks,  | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 11 Registered: 10-2019 |
My car is a 1989 Corniche II, The microrelay's on my board have most of the print gone off them, all I can make out is SH-112D and 12vDC. Thanks | ||
| Omar M. Shams Grand Master Username: omar Post Number: 2007 Registered: 04-2009 |
Dear Edward, I have a spare that I keep for emergencies. I also replaced the micro relays on mine many years ago under guidance from Mr Treacy. It has been many years since i did this and i have to reconfirm with you which component you want me to get the details of. Can we confirm that they are the 5 larger blue boxes on the board shown above? | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 12 Registered: 10-2019 |
Yes, the 5 blue boxes are the microrelays which were mentioned as a common point of failure in the old post. I was hoping I might find an obvious failed component but the board is visually in good condition. Any help is greatly appreciated Omar, thank you | ||
| Omar M. Shams Grand Master Username: omar Post Number: 2008 Registered: 04-2009 |
Ok Edward. My blue boxes have transparent overs on them and you can see the coil and contacts through the transparent case. I have assumed that mine may be made by Farnell because there is an F logo them. The numbers are 211B on one line and D012-M on the second line. On the third line we have the F logo followed by HB8 on 4 of them and HB2 on one | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 13 Registered: 10-2019 |
Thanks Omar, I will use this to try and locate the parts. I rarely use the heat but on a couple of these cool spring nights its nice to have! | ||
| Jeff Young Frequent User Username: jeyjey Post Number: 422 Registered: 10-2010 |
'F' is probably for Fujitsu: https://www.fujitsu.com/us/pdut/detail/1184935/relays/FBR211 Summary: obsolete; no pin-compatible replacements. The 'B' part controls the pin-out and sensitivity, so you definitely need a 211B. 'D012' states the voltage, so that's also a must. There can be a 'S' or an 'N' in front of the 'B' for flux-free and plastic-sealed: either would be fine. The 'M' specs gold-overlay-silver contacts, but 'P' for gold-overlay-silver-paladium would also be fine. Put that all together and you're looking for one of these: FBR211BD012M FBR211BD012P FBR211SBD012M FBR211NBD012M FBR211SBD012P FBR211NBD012P 4Star claims to have some of the last one: https://www.4starelectronics.com/part_detail/FBR211NBD012P20.html You'd probably need to go in with some other interested parties and order a bunch, but it's worth asking to see if they'd sell 5 or 10 of them. | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 14 Registered: 10-2019 |
great information, thanks for that! Are these the main components likely to fail on the board? theres also a vertically mounted transistor with a heat sink I was looking at | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 15 Registered: 10-2019 |
 | ||
| Jeff Young Frequent User Username: jeyjey Post Number: 423 Registered: 10-2010 |
That's probably a 5V voltage regulator rather than a transistor. I don't think it's very likely to fail, though. The two electrolytic capacitors might though. (The orange and blue "cans" on either side of it.) All the little yellow capacitors are films, and are extremely unlikely to fail. There are a few blue cans lying down on the board -- those could be more electrolytics, or they could be tantalums. Can you get the writing off of any of them? The diodes on the SYII cars tend to fail, but they're the little black ones rather than the orange glass ones used on this board. I think the orange glass ones are pretty durable. Any heat marks on the two large black resistors next to the relays? | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 16 Registered: 10-2019 |
You're right, its a voltage regulator. The print on the blue caps looks like 63V on one and 47u T on the other.there doesn't appear to be any heat marks on the resistors. | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 17 Registered: 10-2019 |
These should help  | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 18 Registered: 10-2019 |
 | ||
| Jeff Young Frequent User Username: jeyjey Post Number: 424 Registered: 10-2010 |
The blue one is 1000uF, 25V. So you just need to find an aluminium electrolytic that has the right lead spacing and is 1000uF, 25V. The orange one is 47uF. Everything on this board is 12V or 5V, so just use the same 25V spec as on the blue one. What about the little blue ones lying down on the board? | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 19 Registered: 10-2019 |
Sorry for the delay, i just returned to my computer    | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 3035 Registered: 06-2009 |
I have no idea how easy (or, more likely, difficult) it is to get this thing in and out for testing, but . . . My experience is that when it comes to electronics such as this you must be very cautious not to "do too much" at any one time, which can make it very difficult to determine when you've fixed the issue you've been having if you accidentally introduce another (or others). If you have any way of doing one item at a time, and testing between each, then do so. If not, then at the very least try to deal with the minimum number of replacements on the PCB at any one pass. Even if you wanted to replace each and every component, it would be ideal if you could do every single one as its own step. I know that's generally not realistic, but the general principle applies. Make the fewest replacements you can between each testing pass. Brian P.S. My personal experience with those "canned" electrolytic capacitors is that they will generally show a bit of bulge, most often in the form of a dome where the X crosses over the top, if they've gone bad. | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 20 Registered: 10-2019 |
Overheating the board and/or components is something to be aware of while soldering. I plan to change the microrelays first and then check the system. Now that I've had the board out and reinstalled its not to difficult to access it. | ||
| Jeff Young Frequent User Username: jeyjey Post Number: 425 Registered: 10-2010 |
Bulging electrolytics are usually due to overheating. But they can also dry out which will cause their equivalent series resistance to fall -- which may produce oscillation in some circuits (most commonly anything with feedback, such as a voltage regulator or op-amp). It's hard to guess what the 3 lying down ones are doing without a schematic, so I'd be inclined to factor in Brian's recommendation and replace just the two big ones smoothing the voltage regulator. I suspect the relays are dying because they don't have flyback diodes (which will cause undue arcing in their contacts as the magnetic field in the coil collapses). For whatever reason the automotive industry was slow on this one (my '02 Vanquish suffers from the same in the hydraulic pump circuit). I'd replace all 5 relays. But I'm a DIY in both automotive and electronics, so YMMV. Cheers, Jeff. | ||
| Jeff Young Frequent User Username: jeyjey Post Number: 426 Registered: 10-2010 |
Here's a headphone amplifier I built. Note that each relay has a flyback diode. ;)  | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 21 Registered: 10-2019 |
Nice work! I'll be ordering the components today and begin replacing them soon. The problem I'm trying to rectify is that when I switch on the heater, it blows warm for approximately 30 seconds and then blows cold, going back to blowing warm intermittently. The AC works fine and defrost blows warm consistently (although not Hot). I've changed the heater tap and all sensors on the thermostat housing. When I check the voltage at the heater tap, I'm only getting around 4 volts after the engine warms up, not 12V. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 3036 Registered: 06-2009 |
Jeff, I can believe the overheating theory. The situation I've dealt with was with Vizio TVs, and in an early plasma series that was known for failure in these capacitors. Given how many of these sets failed (and were sadly junked because no one really fixes this stuf except dedicated DIY-ers) and the different suppliers over time for said capacitors, it had to be a design flaw of some sort. But I also have to say the initial failure was not "fast." I think the TV was at least 5 years old, possibly closer to 10. One of these days I need to try my hand at rebuilding the Lucas Opus distributor PCB from SRH33576, as I'm sure the failure in that is from one of the things on the board (which one, I'm not sure, but the instructions for rebuilding give you all the "likely culprits" in the list of things to replace). As an aside, I've used Mouser Electronics to source quite a few "electronic doodads" over time. That's the US website, but it appears they have other online presence worldwide. Brian | ||
| Jeff Young Frequent User Username: jeyjey Post Number: 429 Registered: 10-2010 |
Yeah, Mouser does a thriving business worldwide. They're great for stuff in production, but don't keep any stock of obsolete parts. For those you have to go to the distributors that keep old stuff (primarily for the military). Trouble is they're usually woeful at dealing with small customers -- an area Mouser excels in. I did manage to get business accounts with Rochester Electronics and NJ Semi, but a lot of paperwork was involved.... | ||
| Larry Halpert Experienced User Username: larry_halpert Post Number: 186 Registered: 09-2003 |
Is Mr. Treacy still reachable? I haven't seen him on these boards in a long while. | ||
| michael vass Frequent User Username: mikebentleyturbo2 Post Number: 648 Registered: 07-2015 |
Nice work Jeff! , hope Richard is still reachable! Mike | ||
| Edward Mckinley New User Username: ed_mckinley Post Number: 23 Registered: 10-2019 |
I've ordered the cpacitors, the votage regulator (just in case) and the relays. However, I was unable to source the newer Fujitsu relays. I found the original older OUDH-SH-112D on e-Bay Hong Kong so hopefully they will do the trick | ||
| David Gore Moderator Username: david_gore Post Number: 3693 Registered: 04-2003 |
Richard may be contacted through his business, I have no access privileges that would show his access history but I suspect he may visit from time to time. http://www.spurparts.com.au/ |
