November 22, 2017 - Back in stock - thanks for waiting
January 2019: kit now includes a solder masked, silk screened circuit board
The PK-4 SSR keyer kit - 10/05/2005
05/21/2020: put a PK-4 demo video on Youtube .
12/23/2013: see the new SMT Keyer kit, PK-4 version
The PK-4 SSR is the latest in the PK series of keyer kits.
It replaces the popular PK-4 kit but
adds an optional Solid State Relay (SSR) 6 pin chip for
tube keying, similar to the Keyer Accessory kit .
The Solid State Relay is rated at +/- 120 mA and +/- 400 V. Some
cathode keyed rigs such as the Knight T-150
may require the Keyall
due to larger than 120 mA currents. If in
doubt, measure the current and voltage with
The PK-4 is fully pin compatible
with the Norcal keyer.
The PK-4 is pin compatible
with the PK-3, PK-2 and PK-Basic (Tick and K8 chips, too) with the addition of a 10k ohm pullup resistor
between pin 1 and 4 of the keyer chip socket. The PK-4 shares the pot speed
control of the previous PK series and the Norcal keyer but it has a large number of new additional
features. Here are a few highlights:
pot or paddle speed control, 5 to 50 WPM
two 80 character memories plus an 80 character callsign memory
OR optionally two 80 and two 40 character memories
memories & settings retained without power (EEPROM)
Ultimatic or Iambic A or B keying modes
beacon mode, variable delay, up to 60 seconds
adjustable element weighting
variable sidetone frequency
low standby power (about 7 ua at 5 V, with regulator)
small size (1 by 1.5 inches)
Kit price (no doc) is $18.00 + shipping/handling
Kit with optional SSR: price (no doc) is $22.00 + shipping/handling
PK-4 chip (no doc) is $5.00 + shipping/handling
(multiple purchases of the PK-4 chip (no doc), will be
sent in a single anti-static bag)
Printed manuals available for an additional charge or
save money by downloading and printing your own copy of the
hookup diagram .
Don't get sub menus ?? See the
sub menu doc
Print out a Kit
order form to figure your order manually
Or to use a credit card with Paypal, press the add-to-cart below:
to let your browser do the math!
For larger quantity purchases, manual pricing or to combine with other items, just send an email to:
with the items you want and we'll email you a Paypal invoice.
Downloadable files for the PK-4 SSR
The Acrobat files of complex diagrams (like the PK-4 schematic) may not
view well on your computer screen - suggestion: use the magnifier to zoom in
for better detail or print out the file.
pk4ssr2.pdf (58k) - PK-4 SSR schematic
pk4ssrh.pdf (54k) - PK-4 SSR manual in Acrobat format
pk4hu2.pdf (32k) - PK-4 SSR Hookup diagram in Acrobat format
pk4ssrl.jpg (69k) - PK-4 SSR larger picture
pk4diag.txt (1k) - quick PK-4 resistance / voltage checks text file
pk4ts.htm (1k) - PK-4 Troubleshooting guide
pk4menus.pdf (11k) - a PK-4 menu "cheat sheet" by Chuck Carpenter, W5USJ (thanks, Chuck)
stalkin.pdf (16k) - Stalking the Wild Multipress! - an Acrobat file
of a hardware method to solve the problem of pressing 2 or 3 switches at the same time.
modeab.pdf (8k) - an Acrobat file explaning the differences between Iambic mode A and B
ultimat.txt (4k) - a text file on the Ultimatic mode