A new fan for a Tektronix 2465 - Page 1
Forum section: electronics / testgear

author: siggi
author_rank: Regular Contributor
timestamp: November 13, 2013, 07:35:04 pm
content: Hi guys,I recently aquired a beautiful old Tektronix 2465. She's my first scope, and a bit of a fixer-upper. The first thing I had to fix was the main power switch, no biggie, and she works like a charm now.I didn't know about the A/B sweep feature until after I'd bought it, but - WOW!The problem I have is that the fan is unbearably loud. I did manage to reduce the squeeling by lubricating it, but now it just vibrates instead.So, while there's a guy who's restoring these [http://www.antiqueradios.com/forums/viewtopic.php?uid=30281&f=8&t=235478&start=0], the process is pretty painstaking, expensive (he's offering to sell the bearings he had made at what's a very reasonable price for the effort - I'm not complaining) and somewhat risky, given that I'm pretty much all left-hand thumbs. I'm also not sure that I'd get another 3 decades out of a restored motor unless the fan axle is also refinished...I had a hard look, and it turns out there just enough room for an 80x80x25 fan on the back of the scope's case behind the back cover. A fan that size will however pretty much block the case exhaust hole (~53mm diameter) with the fan hub, and also ends up blocking the right-hand (outside) exhaust vents.So, I figure I can replace the original fan by a "standard" 12V 60x60x20mm case fan, which'll leave plenty of room for the exhaust path. To ballpark the fan sizing, I looked at the airflow figures for the 2465A scope's fan, which turns out to be on the order of 24cfm, and which is reasonably easily matched with a 60x60x20 fan - although it'll have to run faster and probably a bit louder.So, I was thinking to give this a try using this fan:http://www.digikey.ca/product-detail/en/PMD1206PKB1-A.(2).GN/259-1403-ND/1249276.I'm also going to copy the 2465A's fan control circuit. This is basically an LM317 with an NTC to drop the unregulated 15V to ~6-12V depending on ambient temperature.Has anyone here done a mod like this? Is there anything I'm missing that would make this a stupid thing to attempt?Now for a noob question (I'm a software engineer dabbling in electronics, bear with me).I have some LM317s in a TO-220 and I figure I'd better heatsink it a little. I think the dissipation will peak at ~220mA*8V (~19 on the unregulated rail, and ~12 out) or ~1.8W. The TO-200 is 80C/W to ambient, and I figure that'd put me in trouble without heatsinking, especially as the fan will be running full at when it's 65C ambient or thereabouts. Do you guys think something like this [http://www.digikey.ca/product-search/en?WT.z_header=search_go&lang=en&site=ca&keywords=HS365-ND&x=14&y=17&formaction=on] do the job?On the face of it at 28C/W*2W+65 ~= 121C it's not outlandish, and I figure I'd be able to put it somewhere where there's a bit of airflow.Apparently if you lose the fan on those old'uns, you'll shortly after lose U800 which is allegedly made of unobtanium, so I'd hate to build my fan controller in constant thermal shutdown.Siggi

author: mtdoc
author_rank: Super Contributor
timestamp: November 13, 2013, 08:02:23 pm
content: Congrats on your 2465. I have a 2467 (same scope but with MCP CRT). Great scopesI would do a search of the excellentYahoo TekScopes group. I know there has been past discussions there about fan replacement on 2465s. You could also ask your question there and will surely get some well informed advice.

author: siggi
author_rank: Regular Contributor
timestamp: November 13, 2013, 10:01:17 pm
content: Thanks, I'll take a look at the !@#$ Yahoo! group. Why do they have to make it so ... weird and difficult?

author: VintageTekFan
author_rank: Regular Contributor
timestamp: November 13, 2013, 11:22:41 pm
content: I did that mod, but I only used a simple 12V regulator and current limiting resistor. I sized the resistor for peak startup current to stay below ~400mA. I'd rather keep the scope cooler than meet the accuracy specs over the spec'd operating temperature, esp. since I have a 'flaky' U800.One thing I did do, however, was mount the TO220 package (and everything else) on the backside of the aluminum case, to use it as a heatsink. It ended up being near the exhaust flow, so it got the forced air cooling anyway. I'll see if I can post a pic when I get home.

author: VintageTekFan
author_rank: Regular Contributor
timestamp: November 14, 2013, 12:10:58 am
content: Picture as promised.After looking at it again, I think I'm going to add in some insulating material under the leads, since the chassis connects to common.

author: GreyWoolfe
author_rank: Unknown
timestamp: November 14, 2013, 01:34:30 am
content: You can get a fan from the eBay user 2465b for $19 USD.

author: Orpheus
author_rank: Regular Contributor
timestamp: November 14, 2013, 01:50:01 am
content: But how could you not listen to advice from a VintageTekFan?Talk about the horse's mouth!

author: edavid
author_rank: Super Contributor
timestamp: November 14, 2013, 02:59:43 am
content: Quote from: siggi on November 13, 2013, 07:35:04 pmThis is folklore. There's no reason to think U800 failures are related to lack of cooling.

author: edavid
author_rank: Super Contributor
timestamp: November 14, 2013, 03:01:17 am
content: Quote from: GreyWoolfe on November 14, 2013, 01:34:30 amNo, you can't. OP wants to replace the custom fan in the 2465, but the eBay item you mention is a replacement for the standard fan used in the later models of the series. It won't fit in a 2465. (Also, it's just a standard computer fan that 2465b has marked up a fair amount.)

author: BravoV
author_rank: Super Contributor
timestamp: November 14, 2013, 05:38:31 am
content: Did I miss anything here ? Why the need for a custom/weird or hard to find fan ?Although I'm not sure if its the same for 2465, but at my 2465B, it uses just standard ordinary 12 Volt fan, any good industrial fan as long with similar or higher current like later generation fan such as old Panaflo (Panasonic)/NMB or SanyoDenki or Nidec should be good enough.Here the original fan came with my 2465B, and its now replaced with a good quality Sanyo Denki fan, and it works flawlessly. Also the replacement fan is a lot quieter than that decaces old design Nidec fan.Photo from my 2465B teardown thread.

author: edavid
author_rank: Super Contributor
timestamp: November 14, 2013, 05:52:14 am
content: Quote from: BravoV on November 14, 2013, 05:38:31 amNope, it's not the same. The 2465 uses a custom fan.ETA: It uses a Siemens1AD3001-OA1AD3001-0A motor, which occasionally turn up on eBay or other sources.

author: BravoV
author_rank: Super Contributor
timestamp: November 14, 2013, 05:57:24 am
content: Quote from: edavid on November 14, 2013, 05:52:14 amAhh .. no wonder, ok, just knew this.This will be noted and could be useful if my local seller trying to offer me a 2465, an advantage for further "deep" bargaining point, thanks.

author: amyk
author_rank: Super Contributor
timestamp: November 14, 2013, 09:31:04 am
content: That is certainly an unusual choice (and construction) of fan motor... could it be replaced with a small brushless motor of the type used for RC planes?

author: siggi
author_rank: Regular Contributor
timestamp: November 14, 2013, 02:06:52 pm
content: Quote from: VintageTekFan on November 14, 2013, 12:10:58 amThanks, this helps a lot, good to see others have done this successfully. Do you use the scope with the back cover on, or "nude" like this?Quote from: amyk on November 14, 2013, 09:31:04 amI've looked around but haven't found anything suitable. The original design is wonderfully quiet until the bearings go, and I'm not sure a random RC motor would be able to match. The R/C motors are typically designed for maximal power/weight ratio, but this motor is all about just being quiet.According to Matthew who did this restoration [http://www.antiqueradios.com/forums/viewtopic.php?uid=30281&t=235478] even the 2465A/Bs with slow running 80mm case fans don't match the original 2465 in the low, low fan sound.NB: Matthew will/is offering this fan motor restoration as a service. It's pricey as there's a lot of manual labor involved - you have to dismantle and unwind the motor before you can get to the bearings.

author: VintageTekFan
author_rank: Regular Contributor
timestamp: November 14, 2013, 11:11:35 pm
content: Quote from: siggi on November 14, 2013, 02:06:52 pmI use it with the back cover on - it originally came rack-mounted, so there are only 4 screws keeping it on.

author: amyk
author_rank: Super Contributor
timestamp: November 15, 2013, 12:00:35 pm
content: Quote from: Orpheus on November 14, 2013, 01:50:01 amQuoteThey can be quite loud at maximum speed but if you run them far below rated power they're usually rather quiet.

author: siggi
author_rank: Regular Contributor
timestamp: November 17, 2013, 10:11:33 pm
content: So I installed that 60x60x20mm fan - it's a Sunon 5000RPM, 27.5cfm model, using the 2465B's fan control circuit. The circuit runs the fan at ~8V at 25C ambient, ramping to ~13V for 65C ambient. The good news is that there's ample space for the fan back there, there's no issue with ventilation or exhaust. The bad news is that even at the lowest speed, the fan is pretty loud.One day when I've accrued sufficient hobby budget, I think I may have Matthew perform his restoration magic on my fan motor, or I may try and buy a replacement. There really is a world of difference between the noise level from the original fan (when not squeeking or rattling) to the fan I installed. At least now it's just a consistently annoying fan noise, and not an ever-changing rattling that'd sometimes find resonance in my workbench :/.

author: VintageTekFan
author_rank: Regular Contributor
timestamp: November 18, 2013, 04:59:19 pm
content: When I originally got my 2465, the fan was melted into a solid blob - no idea how loud it was.

author: siggi
author_rank: Regular Contributor
timestamp: January 21, 2014, 03:29:36 pm
content: I was lucky enough to score a brand-new fan motor on eBay for a very reasonable price. I was surprised to find it, but now my old scope is restored to it's former whisper-quiet fan performance.Well worth the time and money, IMHO, there really is a world of difference in the noise level.

author: vikbez
author_rank: Newbie
timestamp: August 04, 2018, 02:58:31 pm
content: HiI just bought a 2465A with option 01 & 09 and to my surprise it has the old Siemens fan.I'm here because the fan is noisy, but hours count on scope is only 453. Is this normal lifetime for this fan ? (and is this many for the scope ?)Because of this I'm hesitating between buying a NOS fan or replacing it with a DC 12v standard one.Siggi what value did you use for the NTC ? And did you use the 15v unregulated voltage for the old motor assembly ?ThanksEdit: I found the fan control schema for the 12vdc fan in the 2465B service manual so I will just copy it if needed.But still I would like to know the expected lifetime of the original fan. Thanks

author: siggi
author_rank: Regular Contributor
timestamp: August 04, 2018, 05:45:54 pm
content: Quote from: vikbez on August 04, 2018, 02:58:31 pmThe hours count on the scope is intended to be reset on calibration, so it's not (necessarily) a lifetime counter.Before you switch to a case fan, try flushing and re-lubricating the old motor. It's a bit of a PITA, as (IIRC) you need to de-solder the motor from the driver board to gain access to the thrust bearing screw in the back. Once you have the screw out, you can flush the old gunked-up dirt-in-lubrication out with IPA, then put in a couple of drops of oil. I used synthetic 5W-30 IIRC, which made my 485's run nice and quiet again.See Matt D'Asaro's fan rebuild for good pictures of a dissected fan motor:http://antiqueradios.com/forums/viewtopic.php?f=8&t=235478.

author: vikbez
author_rank: Newbie
timestamp: August 04, 2018, 11:55:36 pm
content: Many thanks !I relubricated the motor and it's now perfectly quietHope it will stay that way now, I don't feel like rewinding the motor !

author: Kartika
author_rank: Regular Contributor
timestamp: December 06, 2020, 08:55:08 pm
content: Hiflow Fan replacement for tektronics 2465b 2467bSunonME80201V1 60m3/h First replacement Replacement is almost equal...Second one is stronger 90m3/hPMD1208PKB1-A 90m3/hfan dimesion 80x80x20mmhttps://www.tme.com/ca/en/katalog/dc12v-fans_112524/...

author: Non-Abelian
author_rank: Contributor
timestamp: December 07, 2020, 04:44:56 pm
content: You can find parts for Tek scopes (and almost anything) from qservice electronics.https://www.qservice.tv/

author: Per Hansson
author_rank: Unknown
timestamp: December 07, 2020, 05:33:20 pm
content: Quote from: edavid on November 14, 2013, 05:52:14 amJust thought it worth mentioning that there is a typo in the partno above, it has the letter O instead of the number 0.So the correct partno is: 1AD3001-0ARight now there is a seller of these on eBay, please note I have no affiliation and also no idea if it is actually the correct item.Just thought it worth mentioning since I work with these Siemens article numbers daily and have seen the same mistake countless timeshttps://www.ebay.com/itm/siemens-Motor-1AD3001-0A-From-HP-Spectrum-Analayzer/264274419076

author: factory
author_rank: Super Contributor
timestamp: December 08, 2020, 06:33:28 pm
content: Quote from: Per Hansson on December 07, 2020, 05:33:20 pmThat second hand fan on ePay looks like the one used in my 1980's HP 8640B.David

author: Kartika
author_rank: Regular Contributor
timestamp: October 26, 2021, 09:55:01 pm
content: 2465b 2467b fan replacementHi Flow Fan replacement for tektronics 2465b 2467bSunonME80201V1 60m3/h First replacement Replacement is almost equal...Second one is stronger 90m3/hPMD1208PKB1-A 90m3/hthird replacement almost doble flow rate103.2m3/h; 9GA0812P6G001 SANYO DENKIfan dimension 80x80x20mmhttps://www.tme.eu/hr/en/details/9ga0812p6g001/dc12v-fans/sanyo-denki/https://www.tme.eu/en/details/pmd1208pkb1-a/dc12v-fans/sunon/https://www.tme.com/ca/en/katalog/dc12v-fans_112524/?visible_params=2%2C173%2C181%2C2699%2C174%2C98%2C179%2C183%2C259%2C120%2C117%2C184%2C68%2C74%2C176%2C536%2C77%2C32%2C175%2C23%2C177%2C1774%2C2546%2C178%2C2190%2C1605%2C82&mapped_params=2%3A391%3B174%3A1439649%3B

author: CatalinaWOW
author_rank: Super Contributor
timestamp: November 16, 2021, 08:34:31 pm
content: For those with a noisy, but functional fan on a 2465 (the ones with the hard to repair and unobtainable Siemens motor) I have found a quick, cheap and easy repair. Can't speak to the life of the repair yet, but it is so easy that it might be worth doing several times over your remaining ownership.The solution is to add an auxiliary bearing, outside the case. Create a disk of suitable material (Oilite, Delrin, Nylon or just about any slick plastic) about 10 mm across, and 2 mm thick. Put a 2mm hole in the center. After removing the impeller, slide this bearing over the motor shaft and add a drop of oil. Verify motor runs properly while holding the disk stationary and if necessary adjust position of the disk to make the squall go away. When all is copacetic use a couple of dabs of hot glue to fix it into place.The only critical part of this is getting the hole to fit closely to the shaft without binding.This works because the main wear on the bearings comes on the fan end. The Oilite bushing becomes oversize and the shaft rolls around the circumference of the hole instead of rotating about its center. The auxiliary bearing simply takes over the job.I have attached an stl file for the one I printed for mine. It worked reasonable well immediately but took a very minor amount of enlarging the hole to make the fan start reliably. The scope went from a horrible caterwaul to inaudible.

author: Old ET
author_rank: Newbie
timestamp: January 26, 2022, 05:02:08 am
content: Just a note:The 9GA0812P6G001 SANYO DENKI fan draws way more current than the stock fan, wouldn't want to smoke the power supply? I think it was rated at 3w.

author: Terraqua
author_rank: Newbie
timestamp: December 16, 2022, 07:46:30 pm
content: For Tek 2465 owners with a 'fan motor problem', SurplusGizmoz has 4 original Siemens 1AD3001-0A DC Motors in stock for $30 US (on 16-12-2022)I wanted to buy one, but the $59.05 US shipping costs to the Netherlands (excluding import Taxes and handling costs etc.) is to steep for me...But US citizens can get one for $30,- (and $15 shipping costs I think). They are located in Hillsboro (Oregon).Here is the link:https://www.surplusgizmos.com/Siemens-1AD3001-0A-DC-Motor_p_3144.html

author: Terry Bites
author_rank: Super Contributor
timestamp: October 31, 2024, 11:12:12 am
content: And the second law is baloney!