Making Replacement for MC1466L - Page 1
Forum section: electronics / repair

author: dzarren
author_rank: Contributor
timestamp: May 07, 2018, 08:28:08 pm
content: I found a power supply that uses two of these MC1466L chips.One is missing and the other one is probably for sure busted.I can get this chip on ebay from china, but typically the quality does not seem to be up to par.I have read in a few places that replacements have been designed, but almost all the links seem to be broken.I saw one guy who made a tiny one, that was a direct plug in. I dont need my replacement to be a direct plug in, but if anyone has a schematic for me to make the chip out of through hole components I would be very interested.If there is anything I missed, please let me know! I think the only thing wrong with my power supply is that the chips are broken, so if i can get a replacement for the chips through whatever method, i would be very happy with that. Ive been dealing with a 0-20V 0.25A power supply for doing everything for 3 years now, so it would be cool if i could get something a little bit better, with this repair.thanks!

author: coromonadalix
author_rank: Super Contributor
timestamp: May 07, 2018, 10:52:46 pm
content: transistorised version :https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjt-suo2PTaAhUE7oMKHVemDloQFggoMAA&url=http%3A%2F%2Fchemelec.com%2FProjects%2FMC1466%2FMC1466.htm&usg=AOvVaw3b3wBx9mF4pMZPAu-ig0-M

author: coromonadalix
author_rank: Super Contributor
timestamp: May 07, 2018, 10:54:11 pm
content: a thread here :https://www.eevblog.com/forum/chat/diy-power-supplyfunction-generator/25/finally your smt version :http://tubetime.us/index.php/2014/09/28/a-miniaturized-discrete-mc1466/

author: floobydust
author_rank: Super Contributor
timestamp: May 08, 2018, 04:26:57 am
content: SMT remake was also on Hackadayhttps://hackaday.com/2017/12/31/making-a-classic-chip-from-discretes/, but it so looks so tiny to build by hand.Some discussion herehttps://www.eevblog.com/forum/beginners/mc1466l-power-supply/

author: David Hess
author_rank: Super Contributor
timestamp: May 08, 2018, 12:01:19 pm
content: The first thing I would try is combining two 723s.

author: coromonadalix
author_rank: Super Contributor
timestamp: May 09, 2018, 01:39:41 am
content: the 723 cant go higher than 40v if i recall, the 1466 was 60v, unless you use floating regulator topology, theres a few aplication notes or an example on the web for an 70 v psu mades wth 723i used an tl783 to-220 regulator with an redesigned current limitter.

author: David Hess
author_rank: Super Contributor
timestamp: May 09, 2018, 08:38:07 am
content: The reason for combining two 723s is that they are the least expensive way to gain access to a pair of integrated transconductance amplifiers which cannot supply the same precision if made with discrete parts.The 1466 has the same voltage limits as the 723 which come from the semiconductor process they were built on. The difference is that the 1466 is designed and specified to always operate as a floating regulator using an isolated auxiliary supply. If the same is done with the 723, then the same higher voltage limit applies.

author: Jwillis
author_rank: Super Contributor
timestamp: May 11, 2018, 06:10:50 pm
content: The Quality is fine.They're all new old stock not re-manufactured. I purchased 6 MC1466L and found 1 MC1566L.I've used 1 of the MC1466L for experimenting and installed the same one in a final circuit.All others have never been used so far.Finished project herehttps://www.eevblog.com/forum/projects/diy-mc1466l-power-supply-all-finished/These are obsolete but not impossible to find and quite interesting to use.It's a shame that Motorola dropped them.Hard to find anything like these .But they restructured and dropped all linear products in favor of telecommunications.The MC1466L/MC1566L will go as high as 250 volts

author: David Hess
author_rank: Super Contributor
timestamp: May 11, 2018, 06:50:02 pm
content: Databooks from the 1970s show a lot of linear regulator controllers including not quite clones of the 723. All of them went out of production except the 723.The 1466 was unusual in being designed specifically for constant voltage/constant current adjustable power supplies so there was no way it was going to compete with 723 for the much larger market of power supplies which only required current limiting. This is especially the case when more general purpose and inexpensive parts could be combined to do what the 1466 does but better.

author: Jwillis
author_rank: Super Contributor
timestamp: May 11, 2018, 08:03:03 pm
content: Ya I suppose but It does has features I liked. The internal referenced 0 volt is handy .The internal short protection because I'm such a klutz.It seems really stable to with really fine adjustment. And the 250 volts might come in handy in later projects.It was really easy to use to.The newest one I have is dated 2002 .Oh well.

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: May 13, 2018, 04:21:24 pm
content: I used the MC1566L to build a high performance, high voltage power supply some years ago. It was variable, up to 1,000 volts, the accuracy and stability exceeded .001%, the limit of the test equipment. It would be quite difficult to produce similar performance using today's voltage regulator chips to achieve similar specs. Granted, it is a little more complicated and requires a floating power supply but that can be a very good advantage. It combines both voltage and current regulation in one package and it is quite accurate in both modes. It does require careful design of the resistors and I do not recommend straying from the recommended circuitry, that can cause unexpected problems.If you read the data sheet carefully, it states that the voltage limit is unlimited, limited only by the pass transistor ratings, so yes it can go well beyond 250V. I cannot say how well a discrete version of the chip performs, be advised that a discrete version may or may not completely duplicate the chip accurately. It is unfortunate that Motorola discontinued this chip but they are available yet, I advise caution on overseas sources, they might not be genuine.

author: dzarren
author_rank: Contributor
timestamp: May 13, 2018, 10:43:17 pm
content: Well I hastily ordered two on ebay, but its possible they may not be real, and might just have the number stamped on it.Is there anyone here on the forum that has a few they can spare? I would love to purchase two just to get this power supply working, it will be my first decent power supply. I've been limited to 1/4 amp for many years now.If you had a couple, I would be glad to pay anything you needed to get them over to me, if you have any to spare.Thanks!

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: May 14, 2018, 03:34:26 am
content: First, the 1466L/1566L were made only in ceramic dip, plastic is a dead giveaway they're fake. I do not know the exact date Motorola discontinued them off the top of my head but I am pretty sure they were dropped before 2000 and likely somewhat earlier, I may have that data in my archives but not that easy to get at these days.I may have a couple of spare 1566L, let me check my inventory.

author: Jwillis
author_rank: Super Contributor
timestamp: May 14, 2018, 08:22:49 am
content: These are the ones I got off EBay and they all work .All have a white band around the perimeter.I suppose that's what you mean by ceramic.Another type I picked up is the Fairchild RC4194Nhttp://pdf.datasheetcatalog.com/datasheet_pdf/fairchild-semiconductor/RC4194D_to_RM4194K.pdfjust for playing around with.

author: w9gb
author_rank: Contributor
timestamp: September 16, 2020, 08:39:50 pm
content: Mr. Carlson’s Lab just posted a Video for repairing his bench adjustable power supply that used the Motorola MC1466L. The video is about 1 hour in length.He used the opportunity to design a new regulator board (his supply uses 2) using current production parts (723 regulator).https://youtu.be/37lIpTxUQcE

author: coromonadalix
author_rank: Super Contributor
timestamp: September 18, 2020, 01:25:59 am
content: I was lucky to get 4x of theses mc1466L year 1989 ??