Recent Posts

1

General Technical Chat / Re: Possible to trigger at battery explosions in pagers ?

« Last post by Buriedcode on Today at 04:19:37 am »

I'm frankly surprised that an organisation like that wouldn't check the supply chain - it seems to avoid the problems with cell phones, they opted for the old school pagers, but just bought them "bulk buy" and didn't do any background checking.  Thats a pretty careless move for an organisation that is worried about security enough to not use cell phones.

2

Networking & Wireless / Re: Use Computer as WiFi Network

« Last post by Halcyon on Today at 04:18:24 am »

Some devices allow you to connect to them via an "Adhoc" network. It's basically just a direct wireless link between two devices without a router in between. It's pretty old school these days.

Most TV's will have some way to "cast" video to them. If your TV has the option of Miracast or Wi-Fi Direct, you'll be able to stream your laptop video if you're using Windows 10 or 11. See here.

Otherwise you may wish to consider reconfiguring your network so that your CCTV system is on its own VLAN without internet access.

3

Projects, Designs, and Technical Stuff / Re: Hakko FR-301 Question

« Last post by rfxcasey on Today at 04:13:18 am »

This instrument is a beast.  Right now on HakkoUSA.com outlet is available for about $250 USD (refurbished unit and the older handpiece without quick change).  I think it is a steal at that price!  I just picked an extra one just in case.

I got mine for 170 USD total on Ebay, brand new, shipped straight from Japan. I think I might pick up a few spare parts while I can (before they are discontinued) but to be honest, at this price, it might be worth it to just pick up a spare complete unit. I use a base station version at work 5 days a week and it gets very heavy professional usage and just keeps on going with normal cleaning. The unit I have at work is around 1K so the FR-301 is a great substitute for the home shop/lab.

4

RF, Microwave, Ham Radio / Re: Unexpected Smith chart behavior

« Last post by AJ528 on Today at 04:12:08 am »

I have an GW Instek LCR-916 (https://www.gwinstek.com/en-US/products/detail/LCR-900)

Looking at the manual, it turns out there is a calibration button on it. Cool. That's good to know!

5

Test Equipment / Re: Test Equipment Anonymous (TEA) group therapy thread

« Last post by 44kgk1lkf6u on Today at 04:07:31 am »

What is a non-inverting inverter?  Is it an ordinary buffer?  Or is it what engineers call the Signetics don't gate?

6

Test Equipment / Re: FLUKE 189 DC reading problem [with video]

« Last post by EyeDontKnow on Today at 04:06:44 am »

Here is what may have happened before I noticed this 189 faulty readings...
I was probing an opamp +18v power pin, the probe slipped, bridging the opamp's OUT and +18vdc pin. Small audible spark. (Black probe was connected to Ground.)
This killed the opamp, but was easily replaced. $1
Repair for Fluke ? ...... $100+

7

Test Equipment / HP 8566B Debug/Rebuild

« Last post by MarshallPlexi on Today at 03:38:22 am »

Hello All!

Been a fan of this forum for a while but am just now getting in spectrum analyzer's so I have a mountain of information to process. I picked up what I thought was a fairly decent 8566B from a local shop and found after getting into it that the input attenuator was fried. Luckily I bought a spares 8566B which I thought would help only to find that it's input attenuator was fried too.

I'm picking up a new attenuator tomorrow, and until then, I have nothing I can do to help, so I thought I'd do one of the common mods that have been recommended for the A20 board, and that is to replace C7, a 10uF/25V cap. I didn't have the exact cap so I replaced it with a 220uF/50V cap thinking that more voltage is better and more capacitance should help to stabilize the supply more.

I also installed a 10dB attenuator between the CAL signal and the input of the LIMITER. To my shock and amazement, I can now run RECALL 8 and I see a 100MHz signal there. Granted the front end attenuator is out of circuit, but this is more than I've seen in the past. The shape of the signal is odd. See attached pic.

Here is what I'm getting.

When I run RECALL 8, I get the image of the kinked 100MHz signal, and when I open up my scan to around 3MHz, I get the correct-looking signal.

Do you have any thoughts on what could be causing this?

The final image is what I'm seeing when I run the RECALL 9 routine. I'm not able to adjust the line into view.

I was also able to get MUCH further into the SHIFT+W calibration routine this time so I feel like I'm making progress!

I'm looking forward to learning more about this incredibly built piece of equipment!

Thanks for any council you can provide!

8

Beginners / Re: How do I find the matching solder points?

« Last post by golden_labels on Today at 03:35:42 am »

Some things to observe.

Mind the polarity of capacitors, when placing new ones. For aluminium electrolytic capacitors negative terminal is marked with a thick line on the side of the cylinder. You can see that on your photos. Use them as a reference.

The board seems to be covered in conformal coating. This will give you pain. You’ll have to remove it for soldering. For small area around the solder joints you can just scrape it off with something very sharp. Carefully, both to protect your fingers and the board. On the forum you can find threads discussing the topic.

If you’re going to desolder the capacitors, you believe a capacitor is a culprit, and don’t wish to do in-depth debugging of the problem, just replace them all. They are cheap and if one of them is actually dying, others are likely not in their prime either.

You did mention you soldered pipes before. Note that the solder used for pipes isn’t going to be good for PCB. It has no flux and usually is too thick for comfortable use in electronics. 0.7 mm to 1 mm solder, with flux core will do. Sn60Pb40 alloy is a popular one with low melting point.

9

Microcontrollers / Re: BRNE jump range, is this an ERROR in the Atmel AVR instruction datasheet ?

« Last post by 44kgk1lkf6u on Today at 03:35:32 am »

How long a binary did you get?  I compiled with avr-gcc (Fedora 14.1.0-1.fc40) 14.1.0, with the options -std=gnu2x -Os -mmcu=attiny13 -DF_CPU=1'000'000.  The binary is 80 bytes long with no store instructions.

Code: [Select]

Disassembly of section .text:

00000000 <__vectors>:
   0: 09 c0        rjmp .+18      ; 0x14 <__ctors_end>
   2: 0e c0        rjmp .+28      ; 0x20 <__bad_interrupt>
   4: 0d c0        rjmp .+26      ; 0x20 <__bad_interrupt>
   6: 0c c0        rjmp .+24      ; 0x20 <__bad_interrupt>
   8: 0b c0        rjmp .+22      ; 0x20 <__bad_interrupt>
   a: 0a c0        rjmp .+20      ; 0x20 <__bad_interrupt>
   c: 09 c0        rjmp .+18      ; 0x20 <__bad_interrupt>
   e: 08 c0        rjmp .+16      ; 0x20 <__bad_interrupt>
  10: 07 c0        rjmp .+14      ; 0x20 <__bad_interrupt>
  12: 06 c0        rjmp .+12      ; 0x20 <__bad_interrupt>

00000014 <__ctors_end>:
  14: 11 24        eor r1, r1
  16: 1f be        out 0x3f, r1 ; 63
  18: cf e9        ldi r28, 0x9F ; 159
  1a: cd bf        out 0x3d, r28 ; 61
  1c: 02 d0        rcall .+4      ; 0x22 <main>
  1e: 16 c0        rjmp .+44      ; 0x4c <_exit>

00000020 <__bad_interrupt>:
  20: ef cf        rjmp .-34      ; 0x0 <__vectors>

00000022 <main>:
  22: 88 e0        ldi r24, 0x08 ; 8
  24: 87 bb        out 0x17, r24 ; 23
  26: 18 ba        out 0x18, r1 ; 24

00000028 <.L2>:
  28: 88 bb        out 0x18, r24 ; 24
  2a: 2f e9        ldi r18, 0x9F ; 159
  2c: 36 e8        ldi r19, 0x86 ; 134
  2e: 91 e0        ldi r25, 0x01 ; 1

00000030 <.L1^B1>:
  30: 21 50        subi r18, 0x01 ; 1
  32: 30 40        sbci r19, 0x00 ; 0
  34: 90 40        sbci r25, 0x00 ; 0
  36: e1 f7        brne .-8      ; 0x30 <.L1^B1>
  38: 00 c0        rjmp .+0      ; 0x3a <L0^A>

0000003a <L0^A>:
  3a: 00 00        nop
  3c: 18 ba        out 0x18, r1 ; 24
  3e: e3 e2        ldi r30, 0x23 ; 35
  40: f4 ef        ldi r31, 0xF4 ; 244

00000042 <.L1^B2>:
  42: 31 97        sbiw r30, 0x01 ; 1
  44: f1 f7        brne .-4      ; 0x42 <.L1^B2>
  46: 00 c0        rjmp .+0      ; 0x48 <L0^A>

00000048 <L0^A>:
  48: 00 00        nop
  4a: ee cf        rjmp .-36      ; 0x28 <.L2>

0000004c <_exit>:
  4c: f8 94        cli

0000004e <__stop_program>:
  4e: ff cf        rjmp .-2      ; 0x4e <__stop_program>


10

Other Equipment & Products / Re: CFW for KSGER/Quicko STM32 Soldering Stations

« Last post by wasyoungonce on Today at 03:31:23 am »

Don't get any metal handle, specially the "M8 black", they get terribly warm, way more than just "uncomfortable".
The blue one looks cheap but works well.

Many thanks...too late for me!  hahahaha