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Author Topic: How hot does a Boat Anchor get?  (Read 40543 times)
W8JI
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« Reply #45 on: February 09, 2015, 05:01:19 AM »


Strawman argument. Tom, you continue to use anecdotal personal observations passed off as factual information to deflect the issues.


Strawman argument from real life examples of dozens of radios I own?

Maybe you should not be so picky about someone's data while you are extracting one non-linear effect from complex data and trying to make it apply as a linear rule.  Smiley



« Last Edit: February 09, 2015, 05:12:50 AM by W8JI » Logged
W8JI
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« Reply #46 on: February 09, 2015, 05:02:17 AM »

It is arguable that there are components to which the heat/MTBF relationship applies and there are those  for which heat has little effect because of various design or manufacturing inadequacies - those will fail anyway, quite possibly if not even used. As an example, although hardly BA stuff, is tin whisker formation temperature related?

Peter RZP has both experience and common sense.
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G3RZP
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« Reply #47 on: February 09, 2015, 05:33:16 AM »

I have even seen an equipment fail miserably on Type Approval because of electrolytic failure which was not related to heat or voltage........

A number of companies were producing 100 watt 2MHz marine SSB transceivers in 1971/2, and several of them went to the same DC-DC invertor manufacturer for their very similar power supplies. One part of Type Approval involved subjecting the equipment to vibration and bump testing: the bumps were 40 bumps of about 10g. Our equipment passed: our competitor's failed. In our case, the power supply was mounted such that the electrolytics were horizontal: theirs had the capacitors vertical and because the 'innards' were shorter than the can, vertical bumps meant the innards moved - no packing to stop them. Same capacitors.....

So it is to easy to generalise.......Some items are a bit easier - metal migration in integrated circuit metallisation is well documented at doubling for every 10 degree C rise in temperature. Now in many cases, even at 125 deg C, the current density is such that a life exceeding one or two hundred years is possible. But tunnel diodes, even if unused, have a life in generally in terms of tens of years because the very high doping density means that diffusion is happening at room temperature. So your AGM45 Shrike anti-radiation missile is probably no good by now.....On the other hand, we did a transistor array which was guaranteed to work for a minimum of 30 minutes at 260deg C - and charged accordingly!
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W1BR
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« Reply #48 on: February 09, 2015, 10:48:51 AM »

True Peter, and I have seen numerous early Tantalum electrolytic caps used for bypasses fail, even though they weren't subjected to high ripple currents or varying DC voltages.  I've regrettably owned several Wavetek synthesized generators that would pop a tantalum on a voltage rail with great regularity. I eventually dumped them... no loss, they were massive noise generators and quite unsuited for any meaningful receiver measurements.

Pete
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KG8LB
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« Reply #49 on: February 10, 2015, 03:33:16 AM »

The strawman gives life to dead issues !

No one has said that heat is the ONLY cause for failure .  It is however a very well known and proven fact that heat is a factor in the premature failure of many components . Solid state to tube type .

  Anecdotes and shelf queen statistics cannot change that .
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G3RZP
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« Reply #50 on: February 10, 2015, 04:50:52 AM »

A factor. By no means the only one, though.
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W8JI
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« Reply #51 on: February 10, 2015, 05:36:23 AM »

The strawman gives life to dead issues !

No one has said that heat is the ONLY cause for failure .  It is however a very well known and proven fact that heat is a factor in the premature failure of many components . Solid state to tube type .

  Anecdotes and shelf queen statistics cannot change that .

Stop that silly stuff. This isn't high school.
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W1BR
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« Reply #52 on: February 10, 2015, 07:24:18 AM »

I consider Tom to be a friend; I think friends can have disagreements and civil discussions.  While not always seeing eye to eye, friends usually remain friends and on good terms. Tom certainly knows more than I have forgotten in many areas.

Pete
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KC2QYM
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« Reply #53 on: February 10, 2015, 09:54:01 AM »

I would say that if you smell some burning plastic or melting metal coming from your boat anchors you've exceeded the maximum thresholds.  I would occasionally place my hands on the top of the cabinets to ensure that the equipment isn't getting too hot.  Throw a few muffin fans on top to accelerate air flow exhaust.  How fancy do you want to be?  Your choice.
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W1BR
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« Reply #54 on: February 10, 2015, 09:59:40 AM »

Plastic!!! On a boat anchor??  Heresy!  LOL 
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KD0REQ
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« Reply #55 on: February 10, 2015, 11:57:59 AM »

phenolic.  it doesn't melt so much as it outgasses and shrinks into a nasty hot little ball of nasty.  you may also know it as bakelite and phenolic/fiber terminal strips.  there could also be vinyl wire insulation.  that can fail at tube-heat temperatures, while it pretty much takes a flame to take out phenolic.
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K1DA
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« Reply #56 on: February 10, 2015, 06:05:12 PM »

I remember when Griefkits used a brown material for circuit boards in tube transceives such as the HW 12.  The stuff got sitcky and began to degrade around the two 6GE6 amplifer tubes. 
I began to use muffin type cooling fans  for such units back in the 60's. Now, the guts of a Collins 32S, for example, used components which were a lot more heat resistant.  Why, if Art didn't put a fan on it, it didn't NEED one.  The smell of hot dust was very common though.
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KG8LB
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« Reply #57 on: February 12, 2015, 04:47:58 AM »


A factor. By no means the only one, though.

   And no one has said otherwise .   Wink  Although some try to make it seem they have .

 
The strawman gives life to dead issues !

No one has said that heat is the ONLY cause for failure .  It is however a very well known and proven fact that heat is a  factor in the premature failure of many components . Solid state to tube type .

  Anecdotes and shelf queen statistics cannot change that .

Stop that silly stuff. This isn't high school.

     Nothing silly about correcting your silly strawman distortions and sophomoric exaggerations of what has been said .
« Last Edit: February 12, 2015, 04:57:47 AM by KG8LB » Logged
KM1H
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« Reply #58 on: February 17, 2015, 09:44:11 AM »

Id say that Pete, ZJH, is right on about the strawman comment since it was answered by nonsensical data not even remotely related; typical spin and confuse.
Pete also has a lot more experience actually doing a proper restoration and using than bragging about what is in storage and just looked at instead of regularly used.

The difference is obvious.

Carl
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AC2NZ
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« Reply #59 on: February 21, 2015, 09:05:13 AM »

I have found some in expensive , quiet portable, controllable (simple switch on the fan) computer fans. I want to get some baseline figures. If I think any of them are running too hot for me I want to experiment by just putting the fans on the top of the cases (HK thoughtfully provides cases full of holes), and blow air over the tubes on a parallel axis. The fans are really quiet and I don't want to hack up the radios. I am particularly  interested in running an SB-301 and SB-401 (transmitter and receiver) on top of each other which may present heat problems.

Blowing cold air on a tube tends to shorten tube life. Use the fan to exhaust the heat. Blow cold air on a semiconductor; suck hot air off a tube.
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