Date   

Re: Replacing Power LED/light on TEK 2465BCT

John Ferguson
 

disregard the "??" on the earlier note. this seesm to be something that thunderbird is doing to me.

Chuck really did calibrate it and it runs very nicely now.

On 5/25/19 7:53 PM, John Ferguson via Groups.Io wrote:
Chuck Harris in Maryland re-capped the PS, did some other repairs, and replaced the NVRAM with an FRAM, and calibrated?? one of my 2445b's all for a very reasonable price.?? Shipping from Florida FedEx ground was $39.?? I used the very stout carton it had been shipped to me from the Ebay vendor. IIRC, Foam pads in front of panel and lots of bubble wrap.

john ferguson


On 5/25/19 3:10 PM, oakley@... wrote:
Thanks for all of the responses.

Originally, I glanced at the green "legend" to the right of the ON/OFF mechanical aperture switch and assumed that I was seeing the front of a green LED sitting behind a windowed membrane. Now after looking closer, it's just a colored legend, so the repair or replacement of the green LED just got much easier ;-)

Although my scope appears to be operating quite close to specification, there were no visible calibration stickers on the unit to gauge how long since its last cal. Any recommendations for calibration of my scope (people, place, labs)?

Tom





Re: Replacing Power LED/light on TEK 2465BCT

John Ferguson
 

Chuck Harris in Maryland re-capped the PS, did some other repairs, and replaced the NVRAM with an FRAM, and calibrated?? one of my 2445b's all for a very reasonable price.?? Shipping from Florida FedEx ground was $39.?? I used the very stout carton it had been shipped to me from the Ebay vendor. IIRC, Foam pads in front of panel and lots of bubble wrap.

john ferguson

On 5/25/19 3:10 PM, oakley@... wrote:
Thanks for all of the responses.

Originally, I glanced at the green "legend" to the right of the ON/OFF mechanical aperture switch and assumed that I was seeing the front of a green LED sitting behind a windowed membrane. Now after looking closer, it's just a colored legend, so the repair or replacement of the green LED just got much easier ;-)

Although my scope appears to be operating quite close to specification, there were no visible calibration stickers on the unit to gauge how long since its last cal. Any recommendations for calibration of my scope (people, place, labs)?

Tom



Re: How do posts make it to the email list

Roy Morgan <k1lky68@...>
 

Kevin,

I am *assuming* that a digest collects posts over a moderate time period and those messages mage up that digest.

So if your post and any replies happen on that time interval, they show up on the digest.

Roy

Roy sends.

On May 25, 2019, at 5:55 PM, Kevin Oconnor <kjo@...> wrote:

I have been on this list for a long time. It just dawned on me that there are aspects about it I don’t understand. How can there be a reply to my specific post within the same email digest that my post was published in? (Same digest #) Doesn’t it have to be published, then read, then replied to in another digest?
Kevin



Re: "Volts/Div" knob for Tek 2235 needed [ Tek part No : 366-2148-01]

tom jobe <tomjobe@...>
 

Whoops!
I made a mistake in the last sentence, it should read:
'I have had very good luck using the IRF840 MOSFET for Q9070, and with using the transistor TIP41C for _Q946_ and Q947, and I think those are the only three components on that heatsink plate'
tom jobe...

On 5/25/2019 3:51 PM, tom jobe via Groups.Io wrote:
Your question of how hot the heat sink gets near the MOSFET  Q9070 made me want to check a 2235 I had worked on just enough to get it to run.
This 2235 needed a lot of new power supply parts including the MOSFET Q9070 which was replaced with an ordinary IRF840 (8A, 500V) MOSFET.
After this 2235 had run for a half hour the heatsink was at 112 degrees F when checked next to the head of the screw that holds Q9070 onto the heatsink.
It was no problem to hold your finger on the heatsink at that temperature, and there was no visible evidence of heat on the MOSFET's Molex connector from this 2235's previous life.
The way I understand it, Q9070 chops up the rectified DC coming in from the line voltage as directed by the PWM chip U930 to create the 43 volt DC that powers the primary side of the transformer T948.
I believe the 43 volt supply's current limit is controlled by U930 using different values of R912 to actually set the current limit for the different models of oscilloscope in the 22XX family that use this same power supply architecture.
Getting back to your heat problem, it is hard to imagine that something is loading your 43 volt supply, and that the current limit is wrongly being set high enough to cause the temperature to be too high at Q9070, but I guess anything is possible.
I have had very good luck using the IRF840 MOSFET for Q9070, and with using the transistor TIP41C for Q947 and Q947, and I think those are the only three components on that heatsink plate.
tom jobe...




On 5/24/2019 9:44 PM, donald collie wrote:
I only really need the clear plastic skirt on this knob [minimum], or two
complete knobs [maximum], as I can probably repair the other one, which has
a cracked skirt. Willing to pay for these. Probably also used on other 22xx
types.
Also : I replaced the chopper MOSFET in the psu with a NZ$1-60 generic
type. It gets very hot to my way of thinking - too hot to hold your finger
on the heatsink near it- does anyone know if an exact replacement is
necessary - perhaps a faster type with lower losses. The MOSFET`s molex
socket shows signs of being quite hot over some time [browning]
Thankyou in anticipation for your
reply.........................................................Donald ZL4GX




Re: Packaging 7854 scope for shipment?

Dave Daniel
 

Arrggghhh... see below ....

DaveD


On 5/25/2019 6:49 PM, Dave Daniel via Groups.Io wrote:
Brad,

I have purchased four 7xxx 'scopes and had them shipped to me. None of them were packed well, not even remotely. The fact that they arrived intact has always surprised me. I've also purchased an HP 8566, HP 8660D and other very heavy items, most of which were not packed well.

When contemplating heavy, fragile items, physics is your guide, in particular Newton's second law (F=ma). You have to assume that the package will suffer at least a three-foot fall onto a concrete surface (e.g., from the shipper's conveyor system onto a concrete floor) and plan to protect the instrument from that sudden deceleration.

An instrument packed rigidly in a box that suffers such a drop will experience a very high G-force when the floor decelerates to box to zero m/s. This places tremendous strain on the internals of the instrument. For a 'scope, this includes possibly breaking the internal CRT connections. So the trick is to pack the instrument such that the packaging material will decelerate the abrupt stop against the floor as gently as possible. This requires that you use packing material that is somewhat compliant. Taking the instrument to someone who can package it in semi-rigid plastic-covered spray foam is very good if you can find someone to do this. Uline (expensive) provides kits for doing this yourself, but they are expensive. In my experience, polyethylene foam is the best for this. See, for instance, https://www.thefoamfactory.com/closedcellfoam/polyethylene.html (this is just a reference - I have never used this company, but the graphics are useful). Many products that one purchases contain products packed with this stuff, and I always save it. Barring a decent supply, one can buy it but it is, again, expensive. If you know of a place that routinely unpacks products and tosses the packaging material, sorting through the discarded material can result in finding some of this stuff.

Once one has a sufficient amount of polyethylene foam, the best packaging method is to suspend the instrument inside the box, cushioned on all six sides by the foam. Corner pads can work (think of how a DVD deck is packaged - two Styrofoam end caps which fit around the ends of the deck and keep it suspended in the box; styrofoam does not have much compliance and so transmits the force from a drop of the box directly to the product packed inside, so it is not a good packaging material, but the idea of suspending the 'scope inside two end caps or four
eight, not four
corner pads is valid).

So, to pack a 7854, I would do something like the following:

1. Accumulate sufficient polyethylene foam. Note that polyethylene foam pieces may be cut and glued together using small amounts of epoxy to make custom-sized pieces.

2. Select a box that has at least 2" of space around the 7854. 3" or 4" will be better.

3. I'd lay a piece of foam in the bottom of the box which fits the entire bottom of the box (see #6, below) , cut another piece to fit up against the rear power supply fins and which extends rearward at least 1/2" beyond the rear enclosure that sits above the power supply, thus protecting the connectors on that rear enclosure.

4. Cut a piece of foam that fits between the front of the box and the plug-in bay (ship the plug-ins separately) and which extended up to just below the CRT bezel, leaving the CRT face and front panel controls at least 1/2" clear of the box.

5. Stuff foam down along the sides of the 'scope. These pieces would be longer than they are tall, but they need not run the entire length of the side of the box. The key here is to prevent side motion and provide compliance between the sides of the 'scope and the box. If the pieces move or slip, it won't matter as long as they stay captured between the 'scope sides and the box.

6. Add a final piece of foam between the top the 'scope and the box. Having that piece extend the entire front-to-back length and side-to-side of the top of the box will help protect the 'scope if the package is dropped on the edge at the front top of the package or either top corners.

One could also provide additional compliance by taping the aforementioned pieces to the 'scope (by running the tape around the foam pieces, not taping them individually to the 'scope) and then packing that whole assembly inside another couple of inches of softer foam or bubblewrap to provide a sort of two-stage deceleration protection.

Double-boxing is always a good idea. Using the softer foam or bubblewrap between the two boxes is a variation on the theme in the paragraph above. Peanuts are not useful at all for this. Peanuts are useless for anything with any mass because the packed item works its way through the peanuts. Typically, for something containing a large transformer, the corner of the item where the transformer is located works its way up against the box side, after which no protection is afforded.

Bubble wrap works OK if one uses a lot of good-quality bubblewrap. The stuff from Home Depot and the like is basically useless because the bubbles cannot sustain much pressure before they pop.

Newspaper is right out (to paraphrase Monty Python).

The best thing is to think it through by considering Newton's second law and how the packaging can provide sufficient gentle deceleration  if the package is dropped.

HTH. Sorry for the extended bandwidth.

DaveD


On 5/25/2019 4:23 PM, Brad Thompson wrote:
Hello--

I'm thinking of offering my 7854 FS and I'd appreciate advice on packaging it
for survival  on shipment to U.S. addresses. IIRC, packing the plug-ins and
keyboard separately is advisable,  as is double-boxing the mainframe.
I'd plan on swaddling the scope in multiple layers of bubble-wrap, with a sheet
of resilient foam to protect the front panel.

Our local pack-and-ship store has a bad reputation. Has anyone successfully used a
commercial mover that offers pack-and-ship services?

If packing turns out to be a hassle, I'll list it for local pickup only.

Thanks in advance, and 73--

Brad  AA1IP



Re: 497p front panel cal failure (CF and Ref Lvl)

John Miles
 

Caps are on the way, but I also just discovered the 5kHz scan per division is
actually scanning the same as 50kHz per division. Wonder if that is related to
the cal problem? Decoding issue on a board I suspect?
Could be. There's a chance that you have a low-resistance condition in one of the small epoxy-dipped ceramic caps on the span attenuator board (if I recall correctly, it's been a while). They don't necessarily fail shorted, but they can load down the TTL address and/or data lines to a point where they won't reliably talk to the peripheral ICs. I would have a look at the logic levels on the relevant boards to make sure they're in range.

-- john, KE5FX


Re: OT: App that keeps track of "Or Best Offer" auctions on eBay to tell you what a seller will accept.

Dave Emery
 

On Sat, May 25, 2019 at 02:42:38PM -0700, Kevin Oconnor wrote:

I should have been clearer. What I meant was that, as a competitor
trying to figure out what an item sold for and to price the same or
similar item, past fixed price sales are misleading. An item may
routinely sell for 25% of the fixed price listing through offers and you
will never know that ( the opaque part). The discount seller can
suppress competition this way.
While I hate to let a cat out of the bag, if you are willing to
pay for it (and it does cost a monthly fee) Terapeak (now an Ebay
subsidiary) DOES provide actual selling price information for BIN and
OBO sales. You CAN find out what something really sold for. And the
discounts are usually significant - but not always.

Ebay (in recent years) has decided not to list this info in
completed/sold item listings found by normal Ebay searches (for most
kinds of sales) beyond the official BIN price - but Terapeak has always
had it available along with how many items actually sold.

Mostly this is oriented toward sellers, but a savvy buyer can
also benefit.


--
Dave Emery N1PRE/AE, die@... DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in
celebration of what could have been, but wasn't and is not to be now either."


Re: Replacing Power LED/light on TEK 2465BCT

Siggi
 

On Sat, May 25, 2019 at 6:27 PM Alberto I2PHD <i2phd@...> wrote:

Thanks. Done that, my 'scope has 4810 hours of power on, and 1160 power
cycles.

How do those numbers place my instrument in the average ranking ? Much
used ? Not much used ? Average used ?

The hours count is most likely since last calibration, as the calibration
instructions would have you reset it. I figure this was to keep track of
time since cal, more than total operating hours.


Re: "Volts/Div" knob for Tek 2235 needed [ Tek part No : 366-2148-01]

tom jobe <tomjobe@...>
 

Your question of how hot the heat sink gets near the MOSFET  Q9070 made me want to check a 2235 I had worked on just enough to get it to run.
This 2235 needed a lot of new power supply parts including the MOSFET Q9070 which was replaced with an ordinary IRF840 (8A, 500V) MOSFET.
After this 2235 had run for a half hour the heatsink was at 112 degrees F when checked next to the head of the screw that holds Q9070 onto the heatsink.
It was no problem to hold your finger on the heatsink at that temperature, and there was no visible evidence of heat on the MOSFET's Molex connector from this 2235's previous life.
The way I understand it, Q9070 chops up the rectified DC coming in from the line voltage as directed by the PWM chip U930 to create the 43 volt DC that powers the primary side of the transformer T948.
I believe the 43 volt supply's current limit is controlled by U930 using different values of R912 to actually set the current limit for the different models of oscilloscope in the 22XX family that use this same power supply architecture.
Getting back to your heat problem, it is hard to imagine that something is loading your 43 volt supply, and that the current limit is wrongly being set high enough to cause the temperature to be too high at Q9070, but I guess anything is possible.
I have had very good luck using the IRF840 MOSFET for Q9070, and with using the transistor TIP41C for Q947 and Q947, and I think those are the only three components on that heatsink plate.
tom jobe...

On 5/24/2019 9:44 PM, donald collie wrote:
I only really need the clear plastic skirt on this knob [minimum], or two
complete knobs [maximum], as I can probably repair the other one, which has
a cracked skirt. Willing to pay for these. Probably also used on other 22xx
types.
Also : I replaced the chopper MOSFET in the psu with a NZ$1-60 generic
type. It gets very hot to my way of thinking - too hot to hold your finger
on the heatsink near it- does anyone know if an exact replacement is
necessary - perhaps a faster type with lower losses. The MOSFET`s molex
socket shows signs of being quite hot over some time [browning]
Thankyou in anticipation for your
reply.........................................................Donald ZL4GX


Re: OT: App that keeps track of "Or Best Offer" auctions on eBay to tell you what a seller will accept.

 

Since FVF does not include shipping, their skirt the eBay fee structure but still make a hefty profit if there is ever a buyer.
Wrong! Final value fees DO get subtracted?? from the shipping costs that a seller charges. Even if you use Ebay to buy and print the label!


Re: Packaging 7854 scope for shipment?

Dave Daniel
 

Brad,

I have purchased four 7xxx 'scopes and had them shipped to me. None of them were packed well, not even remotely. The fact that they arrived intact has always surprised me. I've also purchased an HP 8566, HP 8660D and other very heavy items, most of which were not packed well.

When contemplating heavy, fragile items, physics is your guide, in particular Newton's second law (F=ma). You have to assume that the package will suffer at least a three-foot fall onto a concrete surface (e.g., from the shipper's conveyor system onto a concrete floor) and plan to protect the instrument from that sudden deceleration.

An instrument packed rigidly in a box that suffers such a drop will experience a very high G-force when the floor decelerates to box to zero m/s. This places tremendous strain on the internals of the instrument. For a 'scope, this includes possibly breaking the internal CRT connections. So the trick is to pack the instrument such that the packaging material will decelerate the abrupt stop against the floor as gently as possible. This requires that you use packing material that is somewhat compliant. Taking the instrument to someone who can package it in semi-rigid plastic-covered spray foam is very good if you can find someone to do this. Uline (expensive) provides kits for doing this yourself, but they are expensive. In my experience, polyethylene foam is the best for this. See, for instance, https://www.thefoamfactory.com/closedcellfoam/polyethylene.html (this is just a reference - I have never used this company, but the graphics are useful). Many products that one purchases contain products packed with this stuff, and I always save it. Barring a decent supply, one can buy it but it is, again, expensive. If you know of a place that routinely unpacks products and tosses the packaging material, sorting through the discarded material can result in finding some of this stuff.

Once one has a sufficient amount of polyethylene foam, the best packaging method is to suspend the instrument inside the box, cushioned on all six sides by the foam. Corner pads can work (think of how a DVD deck is packaged - two Styrofoam end caps which fit around the ends of the deck and keep it suspended in the box; styrofoam does not have much compliance and so transmits the force from a drop of the box directly to the product packed inside, so it is not a good packaging material, but the idea of suspending the 'scope inside two end caps or four corner pads is valid).

So, to pack a 7854, I would do something like the following:

1. Accumulate sufficient polyethylene foam. Note that polyethylene foam pieces may be cut and glued together using small amounts of epoxy to make custom-sized pieces.

2. Select a box that has at least 2" of space around the 7854. 3" or 4" will be better.

3. I'd lay a piece of foam in the bottom of the box which fits the entire bottom of the box (see #6, below) , cut another piece to fit up against the rear power supply fins and which extends rearward at least 1/2" beyond the rear enclosure that sits above the power supply, thus protecting the connectors on that rear enclosure.

4. Cut a piece of foam that fits between the front of the box and the plug-in bay (ship the plug-ins separately) and which extended up to just below the CRT bezel, leaving the CRT face and front panel controls at least 1/2" clear of the box.

5. Stuff foam down along the sides of the 'scope. These pieces would be longer than they are tall, but they need not run the entire length of the side of the box. The key here is to prevent side motion and provide compliance between the sides of the 'scope and the box. If the pieces move or slip, it won't matter as long as they stay captured between the 'scope sides and the box.

6. Add a final piece of foam between the top the 'scope and the box. Having that piece extend the entire front-to-back length and side-to-side of the top of the box will help protect the 'scope if the package is dropped on the edge at the front top of the package or either top corners.

One could also provide additional compliance by taping the aforementioned pieces to the 'scope (by running the tape around the foam pieces, not taping them individually to the 'scope) and then packing that whole assembly inside another couple of inches of softer foam or bubblewrap to provide a sort of two-stage deceleration protection.

Double-boxing is always a good idea. Using the softer foam or bubblewrap between the two boxes is a variation on the theme in the paragraph above. Peanuts are not useful at all for this. Peanuts are useless for anything with any mass because the packed item works its way through the peanuts. Typically, for something containing a large transformer, the corner of the item where the transformer is located works its way up against the box side, after which no protection is afforded.

Bubble wrap works OK if one uses a lot of good-quality bubblewrap. The stuff from Home Depot and the like is basically useless because the bubbles cannot sustain much pressure before they pop.

Newspaper is right out (to paraphrase Monty Python).

The best thing is to think it through by considering Newton's second law and how the packaging can provide sufficient gentle deceleration  if the package is dropped.

HTH. Sorry for the extended bandwidth.

DaveD

On 5/25/2019 4:23 PM, Brad Thompson wrote:
Hello--

I'm thinking of offering my 7854 FS and I'd appreciate advice on packaging it
for survival  on shipment to U.S. addresses. IIRC, packing the plug-ins and
keyboard separately is advisable,  as is double-boxing the mainframe.
I'd plan on swaddling the scope in multiple layers of bubble-wrap, with a sheet
of resilient foam to protect the front panel.

Our local pack-and-ship store has a bad reputation. Has anyone successfully used a
commercial mover that offers pack-and-ship services?

If packing turns out to be a hassle, I'll list it for local pickup only.

Thanks in advance, and 73--

Brad  AA1IP


Re: Replacing Power LED/light on TEK 2465BCT

Alberto I2PHD
 

On 2019-05-26 0:10, Dan Rae via Groups.Io wrote:

Details for getting that display, too much for me to type out, are in
Appendix A of the Operator's Manual.
Thanks. Done that, my 'scope has 4810 hours of power on, and 1160 power cycles.

How do those numbers place my instrument in the average ranking ? Much used ? Not much used ? Average used ?

--
/*73 Alberto I2PHD*
<<< http://www.weaksignals.com >>>/


Re: 497p front panel cal failure (CF and Ref Lvl)

radioconnection@...
 

Caps are on the way, but I also just discovered the 5kHz scan per division is actually scanning the same as 50kHz per division. Wonder if that is related to the cal problem? Decoding issue on a board I suspect?


Re: Replacing Power LED/light on TEK 2465BCT

Dan Rae
 

On 5/25/2019 2:45 PM, Alberto I2PHD wrote:
On 2019-05-25 16:12, Dan Rae via Groups.Io wrote:

And the Hours counter can be set to
zero or any number you like as part of the calibration process, so...
How can I make my 2465B display the hours count ?
Details for getting that display, too much for me to type out, are in Appendix A of the Operator's Manual.

There's details for setting the hours in the Service manual, but that's about 6 cms thick so I don't want to search.

Are the debug commands of the firmware listed somewhere ?
That's above my pay grade I'm afraid :^)

73 Dan


Re: How do posts make it to the email list

Alberto I2PHD
 

On 2019-05-25 23:55, Kevin Oconnor wrote:

I have been on this list for a long time. It just dawned on me that there are aspects about it I don’t understand. How can there be a reply to my specific post within the same email digest that my post was published in? (Same digest #) Doesn’t it have to be published, then read, then replied to in another digest?
Not everybody is reading postings in digested format... I for one receive in my inbox each message individually... so, if I see a post and reply immediately to it, there is a big chance that the original post and my reply then go in the next email digest.

--
/*73 Alberto I2PHD*
<<< http://www.weaksignals.com >>>/


Re: How do posts make it to the email list

keantoken
 

You can choose to receive messages in a digest or individually. If you receive them individually, you get them as soon as they're posted. If you choose digest, you get them all at once at whatever interval the digest is set to.

On Saturday, May 25, 2019, 4:55:30 PM CDT, Kevin Oconnor <kjo@...> wrote:

I have been on this list for a long time. It just dawned on me that there are aspects about it I don’t understand. How can there be a reply to my specific post within the same email digest that my post was published in? (Same digest #) Doesn’t it have to be published, then read, then replied to in another digest?
Kevin


How do posts make it to the email list

Kevin Oconnor
 

I have been on this list for a long time. It just dawned on me that there are aspects about it I don’t understand. How can there be a reply to my specific post within the same email digest that my post was published in? (Same digest #) Doesn’t it have to be published, then read, then replied to in another digest?
Kevin


Re: Replacing Power LED/light on TEK 2465BCT

Alberto I2PHD
 

On 2019-05-25 16:12, Dan Rae via Groups.Io wrote:

And the Hours counter can be set to
zero or any number you like as part of the calibration process, so...
How can I make my 2465B display the hours count ? Are the debug commands of the firmware listed somewhere ?

TNX

--
/*73 Alberto I2PHD*
<<< http://www.weaksignals.com >>>/


Re: "Volts/Div" knob for Tek 2235 needed [ Tek part No : 366-2148-01]

donald collie
 

Thankyou Tom, i`ll drop him a line..................Don

On Sat, May 25, 2019 at 6:43 PM tom jobe <tomjobe@...> wrote:

One of the members of Tekscopes makes new replacement volt/div knob
skirts for the 2235. I have bought some of them from him and they are
very nice.
He also carries some hard to find good used/tested parts for the 2235
such as the main transformer (T948?), the high voltage multiplier
(U975?), etc.
This link shows what he has in stock for sale on eBay at the moment, he
must be out of those 2235 knob skirts temporarily.

https://www.ebay.com/sch/shockcore/m.html?item=273836542787&hash=item3fc1ee0b43%3Ag%3AHUcAAOSwZQRYf5YX&rt=nc&_trksid=p2047675.l2562
He is a great guy to do business with as his 100% eBay customer
satisfaction rating shows.
I have bought several sets of his new replacement 2235 volt/div knob
skirts and they work perfectly.
About he only way you can make a mess of the knob skirt replacement is
to use too much glue.
A few very tiny dabs of glue/epoxy at the smallest diameter of the knob
register is all you need, and there is a notch that orients the skirt to
the knob just like the original had.
The member name he uses on Tekscopes escapes me at the moment, but you
can contact him through any of his eBay auction pages such as this page
for his 2235 main transformers.

https://www.ebay.com/itm/Tektronix-120-1601-01-SwitchmodeTransformer-for-2213A-2215A-2235-Oscilloscope/273836542796?hash=item3fc1ee0b4c:g:bAQAAOSwnrJbfX~4
tom jobe...








On 5/24/2019 9:44 PM, donald collie wrote:
I only really need the clear plastic skirt on this knob [minimum], or two
complete knobs [maximum], as I can probably repair the other one, which
has
a cracked skirt. Willing to pay for these. Probably also used on other
22xx
types.
Also : I replaced the chopper MOSFET in the psu with a NZ$1-60 generic
type. It gets very hot to my way of thinking - too hot to hold your
finger
on the heatsink near it- does anyone know if an exact replacement is
necessary - perhaps a faster type with lower losses. The MOSFET`s molex
socket shows signs of being quite hot over some time [browning]
Thankyou in anticipation for your
reply.........................................................Donald
ZL4GX






Re: OT: App that keeps track of "Or Best Offer" auctions on eBay to tell you what a seller will accept.

Kevin Oconnor
 

@Jim Potter
I should have been clearer. What I meant was that, as a competitor trying to figure out what an item sold for and to price the same or similar item, past fixed price sales are misleading. An item may routinely sell for 25% of the fixed price listing through offers and you will never know that ( the opaque part). The discount seller can suppress competition this way.
I also see numerous sellers with outrageous shipping and undervalued fixed pricing. Since FVF does not include shipping, their skirt the eBay fee structure but still make a hefty profit if there is ever a buyer. This is against eBay policy, but they don’t do anything about it.
K

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