The Electronics Universe

#24 Heathkit GD-1B grid dip repair and homebrew coils

In this video we have a look at an old Heathkit GD-1B. After a quick repair we test the unit and then build the missing coils that are needed to operate.

EDIT: Sorry but for some reason unknown I lost the footage of the repair.



https://www.youtube.com/watch?v=RI8u8L0RvQI

Information
http://www.heathkit.nu/heathkit_nu_GD...
Manual
http://www.radiomanual.info/schemi/AC...


Jeff Avery: The coils I wound for my Heathkit GD-1B Dip Meter
http://www.jeffavery.ca/hamradio/hamradio5b.html

Alan w2aew
#52: Tutorial / Basics of a Dip Meter
https://www.youtube.com/watch?v=_HwIL6mqq_k

Last video for 2015
In this episode I look at a UV-5RA that has no receive audio.
With the cheap cost of this radio it makes no sense to take to a professional repair shop since the repair cost would be more than a new radio. What I find is the voice coil in the speaker has broken wires so I attempt to repair it.


https://www.youtube.com/watch?v=mXFdzSFWGdM

scans for a member

#20 Kenwood TM 621A deaf 220 MHZ Receive

In this video I attempt  to repair the 220 MHz receiver in a 621a. I have no service information on this rig but have repaired several of them. There are no free copies of the service manual online that I can find. I use the TM-721 block diagram to trouble shoot. The 721 is a 2 meter 70 center meter unit.



https://www.youtube.com/watch?v=ABNHKbWn7gE

replacement transistor

http://www.ebay.com/itm/NE25139-Dual-Gate-GaAS-MESFET-Replacement-for-3SK184S-Lot-of-5-/120748159991


Kenwood TM-721 service manual
http://www.repeater-builder.com/kenwood/pdfs/tm-721-svc-man.pdf

#18 Kenwood TS 940 DOT on display Chasing down the rabbit hole Pt 1

In this video I have a TS-940 that has the dreaded dots on the display. After doing the regular checks for signals and voltages on the PLL's I decided to start looking for other issues that can cause this problem. So which is causing this problem? Bad wire connectors, cracked solder joints plus PLL unlocked. We will look at the boards and connectors in this part one series. Just some basic visual checks with our eyes. In part 2 we will go to the schematic and start checking signals and voltages.






https://www.youtube.com/watch?v=Gffq13To1zw

In this video I found a National NC-155 sitting on my door step. The receiver is very dirty and shows a lot of signs of many years of abuse. Will it still work with out a lot of repair?

Lets find out.



https://www.youtube.com/watch?v=ORXsGghi_ss

The National NC-155 is a ham-bands-only receiver covering the 80, 40, 20, 15, 10 and 6 meter bands. Has BFO, product detector, three levels of selectivity (5, 3 and 0.6 KHz) and separate RF gain and volume controls. It is a somewhat cost-reduced version of the NC-270, leaving out the crystal calibrator and notch filter. Both radios use dual conversion. The first IF is 2215 KHz using an LC oscillator in the NC-155 and crystal oscillator in the NC-270. Second conversion for both is 230 KHz using a "Patented Ferrite Filter". Changing the coupling between the two halves of the filter provides the selectivity choices.

The NC-155 was introduced in 1961 at a price of $199.95. It was reviewed in QST magazine in July 1962. The matching NTS-3 speaker was an optional accessory. The NC-155 and its speaker both have the "flip-foot", a flip out stand for the front of the set to angle the desk-mounted receiver and speaker up toward the operator.

http://www.ohio.edu/people/postr/bapix/NC155.htm

In this video we look at a tech special TS-50. What we find is smd caps have leaked on the pcb causing corrosion. Someone tried repairing with through hole caps but ended up ripping traces off the board. Part one I will evaluate the repair and remove parts then clean the board. In part 2 I will show you how to repair the missing traces the correct way,




https://www.youtube.com/watch?v=z8MvFtR5l9k

Here is a look at one of the latest component testers from Banggood.com







Banggood.com
http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-p-986954.html

VoltLog
https://www.youtube.com/watch?v=GeEPo9BoRDo

To learn more about these type of testers check out this thread:
EEVblog
$20 LCR ESR Transistor checker project
http://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/