June 2019 - vcf-midatlantic

Help identify Motorola transistor
by Fred Terry 12 Jun '19

12 Jun '19

My name is Fred Terry. I was a member of the VCF list a few years ago but there was an incompatibility with my verizon.net <http://verizon.net/> address and I was dropped. I am not certain of protocol so please excuse. I am trying to revive my Persci 277 but I have a bad T0220 transistor marked with the (Motorola logo) followed by 813 and having a bottom line of 1075-1. I bought the Persci new in the late 70s and have all the manuals but the bad transistor is on the power supply board for which there is no information. I remember when I joined the VCF someone was working with his Persci 277 but I have lost his name. I have registered for the August repair weekend but I live in Cockeysville, Maryland and i am facing a three hour drive. I could avoid the drive if I could get a replacement transistor. I bought my Imsai 80/30 in the late 70s along with the Persci 277, a Diablo printer and a Sol monitor. I have all the manuals and documentation for these components as well as documentation for the CP/M operating system. The Imsai is running and I hope to get the Persci operating again so I can finish the program I was writing. When finished I intend to donate what I have to the VCF Museum. Fred Terry

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Next Workshop is July 20
by Jeffrey Brace 12 Jun '19

12 Jun '19

I’m gonna schedule the next workshop for July 20 & 21. It will be in CDL because the “radio guys” (NJARC) will be using 9032-A. I won’t be there because I will be traveling to St. Louis for my Uncle’s 90th birthday. I will send out a link for signup soon. -- ========================================= Jeff Brace Vice President Vintage Computer Federation

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July workshop?
by Jeffrey Brace 11 Jun '19

11 Jun '19

There has been a request for a July workshop. If there is enough interest, then I will organize it. My feeling is that July 26 & 27 will work best. If I get at least 5 interested, then I will organize for that weekend. Reply to this e-mail if you are definitely interested. Optionally: July 6 & 7 in the usual area (9032-A) with Sandy area rooms available for overnight stay. July 13 & 14 in 9032-A, with no overnight rooms available. July 20 & 21 in the CDL space (Hackerspace) with Sandy area rooms available. -- ========================================= Jeff Brace Vice President Vintage Computer Federation

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Re: [vcf-midatlantic] I don't know if there will be a Maker Faire this year
by Ethan O'Toole 10 Jun '19

10 Jun '19

> [NON-Text Body part not included] When we ran mini makerfaires (~1500 people) we had to pay license fees based on per-attendee roughly. Maybe that expense will be shed for people doing them, but so will the resources they give you. Time will tell. The maker movement won't die. I had to quit my subscription to the magazine, it was just 3d printers over and over. And they changed the sized so they didn't match on the shelf anymore.

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Re: [vcf-midatlantic] Tube Testing - any recommendations
by Sentrytv 10 Jun '19

10 Jun '19

Hi Mike I thought I'd put my two cents in the discussion here. We have quite a few guys in our group that are "tube savvy" and could definitely help you out. First thing I would start with Is obtaining the HealthKit diagram, so you can see what's going on in the circuits. Yes you do have to worry about high voltages.! Determine what the issue is first, if you have a trace or deflection, or not, if you have correct power supply voltages or not. Having the right tools like a VTVM for a tube related to repair is absolutely necessary. A digital meter will work as long as you have one that can handle the voltages. Most likely the power supply has bad capacitors, it but that Has yet to be determined by checking the voltages in the power supply, against the schematic diagram if possible. Having some new tubes on hand and swapping them out is not a bad idea, but usually not the best way to troubleshoot. If you plan on working on more tube type equipment, a tube tester is absolutely necessary! I am available for help if needed. And bringing it to one of our workshops is probably a good idea if you're in the area. Mike R. Sent from: My extremely complicated, hand held electronic device. > On Jun 10, 2019, at 10:17 AM, mwillega via vcf-midatlantic <vcf-midatlantic(a)lists.vcfed.org> wrote: > > <mime-attachment>

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Re: [vcf-midatlantic] I don't know if there will be a Maker Faire this year
by Jeff G 10 Jun '19

10 Jun '19

Just got an announcement that the Philly Mini Maker Faire is still going on despite this, but yeah not good news either way. Here's the link to the Philly event on October 6th, 2019: https://philly.makerfaire.com/ Jeff (aka Bags)

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Re: vcf-midatlantic Digest, Vol 13, Issue 9
by Jeff G 10 Jun '19

10 Jun '19

Where are you located? I have a tube tester (several actually) Jeff (aka Bags) On Mon, Jun 10, 2019 at 12:07 PM <vcf-midatlantic-request(a)lists.vcfed.org> wrote: > Send vcf-midatlantic mailing list submissions to > vcf-midatlantic(a)lists.vcfed.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.vcfed.org/mailman/listinfo/vcf-midatlantic > or, via email, send a message with subject or body 'help' to > vcf-midatlantic-request(a)lists.vcfed.org > > You can reach the person managing the list at > vcf-midatlantic-owner(a)lists.vcfed.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of vcf-midatlantic digest..." > > > Today's Topics: > > 1. Tube Testing - any recommendations (mwillega) > 2. Re: Tube Testing - any recommendations (Evan Koblentz) > 3. Re: Tube Testing - any recommendations (Chris Fala) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Mon, 10 Jun 2019 10:17:59 -0400 > From: mwillega <mike(a)willegal.net> > To: vcf-midatlantic(a)lists.vcfed.org > Subject: Tube Testing - any recommendations > Message-ID: <EF8D7552-F12A-490D-BB87-61C0CC3BAB15(a)willegal.net> > Content-Type: text/plain; charset=utf-8 > > Hi all, > > I?m about to embark on my first restoration of a piece of tube based test > gear. It?s an old Heathkit Oscilloscope from the early 70s. I am looking > for recommendations for approaches to tube testing. Do I seek out or > build a tube tester or just test in circuit. Anything else that I should > look out for, besides the usual concerns about high voltages on the > chassis, and old degraded components. > > Regards, > Mike Willegal > > ------------------------------ > > Message: 2 > Date: Mon, 10 Jun 2019 11:09:06 -0400 > From: Evan Koblentz <evan(a)vcfed.org> > To: vcf-midatlantic <vcf-midatlantic(a)lists.vcfed.org> > Cc: mwillega <mike(a)willegal.net> > Subject: Re: [vcf-midatlantic] Tube Testing - any recommendations > Message-ID: <664e3d37-3600-19ff-36c5-2c5367ce3f9e(a)vcfed.org> > Content-Type: text/plain; charset=utf-8; format=flowed > > > > Do I seek out or build a tube tester or just test in circuit. Anything > else that I should look out for, besides the usual concerns about high > voltages on the chassis, and old degraded components. > You might want to ask the NJ Antique Radio Club. They do this all the time. > > > ------------------------------ > > Message: 3 > Date: Mon, 10 Jun 2019 11:12:23 -0400 > From: Chris Fala <chrisjpf33(a)gmail.com> > To: vcf-midatlantic <vcf-midatlantic(a)lists.vcfed.org> > Subject: Re: [vcf-midatlantic] Tube Testing - any recommendations > Message-ID: > < > CAJCHokjMnpED5NSRON3fzk8BxG5oXJD3oUkvA+iJMDa0QWZUFw(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > There is a Facebook group called Vintage Electronic Test Equipment and a > lot of the guys there post stuff about tube testers. Might be a good > resource for information > > > > . > > On Mon, Jun 10, 2019 at 10:18 AM mwillega via vcf-midatlantic < > vcf-midatlantic(a)lists.vcfed.org> wrote: > > > Hi all, > > > > I?m about to embark on my first restoration of a piece of tube based test > > gear. It?s an old Heathkit Oscilloscope from the early 70s. I am > looking > > for recommendations for approaches to tube testing. Do I seek out or > > build a tube tester or just test in circuit. Anything else that I should > > look out for, besides the usual concerns about high voltages on the > > chassis, and old degraded components. > > > > Regards, > > Mike Willegal > > > End of vcf-midatlantic Digest, Vol 13, Issue 9 > ********************************************** >

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Re: [vcf-midatlantic] Tube Testing - any recommendations
by Chris Fala 10 Jun '19

10 Jun '19

There is a Facebook group called Vintage Electronic Test Equipment and a lot of the guys there post stuff about tube testers. Might be a good resource for information . On Mon, Jun 10, 2019 at 10:18 AM mwillega via vcf-midatlantic < vcf-midatlantic(a)lists.vcfed.org> wrote: > Hi all, > > I’m about to embark on my first restoration of a piece of tube based test > gear. It’s an old Heathkit Oscilloscope from the early 70s. I am looking > for recommendations for approaches to tube testing. Do I seek out or > build a tube tester or just test in circuit. Anything else that I should > look out for, besides the usual concerns about high voltages on the > chassis, and old degraded components. > > Regards, > Mike Willegal

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Re: [vcf-midatlantic] Tube Testing - any recommendations
by Evan Koblentz 10 Jun '19

10 Jun '19

> Do I seek out or build a tube tester or just test in circuit. Anything else that I should look out for, besides the usual concerns about high voltages on the chassis, and old degraded components. You might want to ask the NJ Antique Radio Club. They do this all the time.

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Tube Testing - any recommendations
by mwillega 10 Jun '19

10 Jun '19

Hi all, I’m about to embark on my first restoration of a piece of tube based test gear. It’s an old Heathkit Oscilloscope from the early 70s. I am looking for recommendations for approaches to tube testing. Do I seek out or build a tube tester or just test in circuit. Anything else that I should look out for, besides the usual concerns about high voltages on the chassis, and old degraded components. Regards, Mike Willegal

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