Identify this components please.
Hi,
Strapped directly across the b-e junction of a TIPL755A bipolar in a SMPS out of a HP54502A scope is the following - Body - cylindrical, black plastic, 5/8" long by 1/4" dia. Body markings - MCS MTS 90A. Leads - two, axial. PCB marking - S1. Polarity markings - nil. Condition - s/c. Naturally I don't have a schematic but my guess is that it's some sort of over-voltage clamp. A great deal of googling hasn't helped me so any info would be much appreciated. Happy Holidays - Joe |
Identify this components please.
Joe McElvenney wrote in message
... Hi, Strapped directly across the b-e junction of a TIPL755A bipolar in a SMPS out of a HP54502A scope is the following - Body - cylindrical, black plastic, 5/8" long by 1/4" dia. Body markings - MCS MTS 90A. Leads - two, axial. PCB marking - S1. Polarity markings - nil. Condition - s/c. Naturally I don't have a schematic but my guess is that it's some sort of over-voltage clamp. A great deal of googling hasn't helped me so any info would be much appreciated. Happy Holidays - Joe inductor ? |
Identify this components please.
Joe McElvenney wrote: Hi, Strapped directly across the b-e junction of a TIPL755A bipolar in a SMPS out of a HP54502A scope is the following - Body - cylindrical, black plastic, 5/8" long by 1/4" dia. Body markings - MCS MTS 90A. Leads - two, axial. PCB marking - S1. Polarity markings - nil. Condition - s/c. Naturally I don't have a schematic but my guess is that it's some sort of over-voltage clamp. A great deal of googling hasn't helped me so any info would be much appreciated. Happy Holidays - Joe It doesn't appear to have the schematic but the 'service' manual is available for free at the manufacturer's website: http://www.home.agilent.com/agilent/techSupport.jspx?pid=54502A%3Aepsg%3Apro&pageMode= MN&cc=US&lc=eng -- http://improve-usenet.org/index.html aioe.org, Goggle Groups, and Web TV users must request to be white listed, or I will not see your messages. If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm There are two kinds of people on this earth: The crazy, and the insane. The first sign of insanity is denying that you're crazy. |
Identify this components please.
On Mon, 22 Dec 2008 13:35:11 +0000, Joe McElvenney
put finger to keyboard and composed: Hi, Strapped directly across the b-e junction of a TIPL755A bipolar in a SMPS out of a HP54502A scope is the following - Body - cylindrical, black plastic, 5/8" long by 1/4" dia. Body markings - MCS MTS 90A. Leads - two, axial. PCB marking - S1. Polarity markings - nil. Condition - s/c. Naturally I don't have a schematic but my guess is that it's some sort of over-voltage clamp. A great deal of googling hasn't helped me so any info would be much appreciated. Happy Holidays - Joe Is there an S2? I don't know what a coil would be doing across a B-E junction, but can you measure any inductance? I can't imagine that S1 is an OV clamp, unless it is a reverse biased diode for protection against excessive negative voltages. But then a diode would have a polarity marking. Does the body of the device have sharp ends (like a 1N4007 diode) or are the ends rounded like a resistor? - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
Identify this components please.
Hi everybody,
It appears that the components is a thermal switch that shunts base current away from the switching transistor when the ambient board temperature reaches a certain figure due to a fault condition such as an overload or a fan failure. I have the HP service manual but it doesn't have a parts list or schematic for the SMPS, so I'm reduced to guessing my way round the circuit. The unit works without the temperature switch but I can use a locally available substitute while looking for the real thing. I am currently investigating a source of C122F1 SCR's so I may fix the +5.2V regulator. BTW, I gave the marking incorrectly - twice; they are MCI MTS 90A. Thanks for your help - Joe |
Identify this components please.
On Wed, 24 Dec 2008 19:58:37 +0000, Joe McElvenney
put finger to keyboard and composed: Hi everybody, It appears that the components is a thermal switch that shunts base current away from the switching transistor when the ambient board temperature reaches a certain figure due to a fault condition such as an overload or a fan failure. I have the HP service manual but it doesn't have a parts list or schematic for the SMPS, so I'm reduced to guessing my way round the circuit. The unit works without the temperature switch but I can use a locally available substitute while looking for the real thing. I am currently investigating a source of C122F1 SCR's so I may fix the +5.2V regulator. BTW, I gave the marking incorrectly - twice; they are MCI MTS 90A. Thanks for your help - Joe US patent number 5,512,732 ... http://www.google.com/patents/pdf/Sw...0K xc1wO6MuFw .... refers to a "ferrite reed switch" obtained from Therm-O-Disc, Inc of Mansfield, Ohio, model MTS-90B with a Curie temperature of 90 degC. US patent number 4,509,029 ... http://www.google.com/patents/pdf/Th...sZS7rwyBfNBD3Q .... assigned to Midwest Components, Inc, (MCI?) describes a thermal switch consisting of "a reed switch surrounded by an annular collar made of ferrite material and a pair of annular permanent magnets". The latter patent refers to a brochure entitled "Thermal Reed Switches" by Tohoku Metal Industries. I suspect that "MTS" may stand for "Magnetic Temperature Switch". There are plenty of Google hits for this term. AFAICT, Midwest Components, Inc is a division of Therm-O-Disc, Inc: http://www.thermodisc.com/index.asp This site lists an MTS90B part made by MCI: http://www.mwcomponents.com/~midwest...ser_part=mts90 - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
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