Heathkit HR-1680 PC Card Extender. Heathkit HR-1680 PC Assembly Extender Assembly

Transcription

1 Heathkit HR-1680 PC Assembly Extender Assembly Version Date Author Comment 1.0 August 15, 2009 RM Groh Original draft Table of Contents Introduction...1 Heathkit s Approach...2 Parts Required...3 Assembly Process...3 Thanks To The Following:...6 Pictures Picture 1 Inside of HR Picture 2 Original Extender Assembly...2 Picture 3 Extender in Use...3 Picture 4 Typical Wire and Dimensions...4 Picture 5 Strip off the jacket on the wire...4 Picture 6 Solder pin and socket on end wires...5 Picture 7 Completed Extenders in My HR Introduction The Heathkit HR-1680 needs some form of printed circuit (PC) extender to have the slightest chance of servicing the plug in circuit cards. Picture 1 Inside of HR /15/2009 Bob Groh,WA2CKY Page 1 of 6

2 As Picture 1 indicates, three of the printed circuit cards plug down into the chassis. There is a shield between the boards and the boards are mounted to the shield on 2 threaded standoffs. It is virtually impossible to reach the components or the traces between components (the traces are on the back side of the PC board). The boards have to be plugged into an extender so they are 4 or 5 inches up in the air and both the front and the back of the PC board are available for access by test instruments. Heathkit does provide a process to build a set of extenders but the major parts (the socket and pin assembly) are not obtainable now. With the help of several other hams, I have been able to find a source (actually sources) for pins and sockets which can be used to build an acceptable set of extenders. Heathkit s Approach The HR-1680 plug in PC assemblies used 6-contact pin and socket assemblies two assemblies on one card and three on the other two. The pins were a nominal in diameter and the spacing between adjacent contacts was 0.25 inches. The extender assembly (there were 3 of them i.e. enough to all one board to be extended up for servicing) was constructed with a 6-pin assembly at one end and a 6-socket assembly at the other and regular insulated wire used to tie the two together. The next two pictures show one extender assembly and a typical use. Picture 2 Original Extender Assembly 8/15/2009 Bob Groh,WA2CKY Page 2 of 6

3 Picture 3 Extender in Use Unfortunately the parts used to build the extender are no longer available so we need an alternative. Parts Required Luckily the proper sized sockets and pins are still available. However they are not available (at least in the same configuration of multiple pins and sockets) except as individual pins and sockets intended for crimping onto insulated wires. Description Tyco/Amphenol PN Mouser PN Pin, in, AWG wire Socket, in, AWG wire Note: DigiKey also has these parts So we decided to use these parts and simply solder them onto the end of solid AWG 14 wire. Not optimum but they work. The Amphenol parts are inexpensive ($0.05 each in 100 piece lot). For the wire, I used regular ground house wiring (25 foot roll was about $9.00 at Home Depot). Assembly Process 8/15/2009 Bob Groh,WA2CKY Page 3 of 6

4 Picture 4 Typical Wire and Dimensions As mentioned, we used regular duplex house wiring (AWG ground). We decided on 4-3/4 inches from bottom of socket to the top of the pin and that made the wire about 3-1/2 inches long with ¼ inch of insulation stripped from each end for soldering on the pin and socket. To economize, we used not only the insulated wire but also the bare ground wire figuring that we would put the bare wire assemblies between the insulated ones. Picture 5 Strip off the jacket on the wire We cut the 14-2 cable into 3-1/2 lengths and then stripped off the outer jacket and the pulled out the white and black insulated wires as well as the bare copper wire. The insulated wires had about ¼ of insulation stripped off each end. 8/15/2009 Bob Groh,WA2CKY Page 4 of 6

5 Picture 6 Solder pin and socket on end wires I crimped the socket on one end and the pin on the other end and then soldered both ends. I double checked the length against my little scale drawing more to keep them the same than worrying about exact length. Picture 7 Completed Extenders in My HR /15/2009 Bob Groh,WA2CKY Page 5 of 6

6 I then tried my new extenders in my HR It takes a bit of care to get all 18 of them lined up and inserted top and bottom. I basically started at one end and carefully worked to the other end. I was worried that the board would flop around but the wires are sufficiently stiff enough the board is reasonably stiff. I think I can work on it and finally trouble shoot my HR Thanks To The Following: Many thanks to my good friend, John Klingelhoeffer, WB4LNM, another ex-heathkit employee from the 1970 s who provided encouragement and some strong leads in finding the right connectors. My thanks also to other s on the Yahoo Heathkit list who provided leads and to the ham (sorry, I lost your name) who provide a copy of the extender drawings from the HR-1680 manual. 8/15/2009 Bob Groh,WA2CKY Page 6 of 6