Visible crew/equipment: At Rampart, when Gage and DeSoto walk into the staff lounge, where Dixie and Dr. Brackett are seated at the table, there is an actor's T-mark on the floor behind Dixie, where DeSoto stands.
Visible crew/equipment: When Roy is in the ER due to the dizziness, two actors' T-marks are visible on the floor near the door, where moments later Dr. Bracket and Dr. Early stand before leaving. Additionally, Dr. Early's mark (during The Exam) becomes visible when Dixie shifts her position, just as Dr. Bracket asks, "Any pain here, Roy?"
Continuity mistake: In nearly every episode, the dark blue jackets that Gage and DeSoto wear suddenly appear and/or vanish and then reappear, numerous times, while en route in their squad, or when they pull into the stationhouse and Rampart. Since stock footage is usually used when showing all the guys getting into their vehicles, Johnny's hair length may differ as well.
Loose Ends - S6-E12
Visible crew/equipment: When the guys bring Brackett to the hospital after his car accident, two white tape, and one black tape actors' T-marks are all visible on the floor in the ER.
Peace Pipe - S2-E5
Visible crew/equipment: Just after the drunk driver is loaded onto the ambulance, when Roy tells Johnny about Debbie's pulse and respiration, and that she's in bad shape, then also when Roy tells Captain Stanley to make it quick, a crew member sitting atop a ladder with set lighting beside him are visible in the background.
Pressure 165 - S5-E7
Continuity mistake: While Johnny and the doctor are in the pressurized chamber with the diver, the guy outside the chamber tells them that they're at 165 and vetting, as he holds the mic up to his mouth with his left hand, but when it cuts to the interior shot, the mic is held up in his right hand.
Fair Fight - S6-E5
Visible crew/equipment: After the cave-in rescue, when Dixie, DeSoto and Gage are in the ER, Gage washes his face and as he comments that he wasn't cut out to be a mole, two tape marks are visible at his feet.
Visible crew/equipment: When Mr. Grady (self-defense instructor) is in the ER, being examined by Dr. Brackett, there is a visible T-mark on the floor behind Gage.
Visible crew/equipment: After Chet is brought to the ER, Gage goes to the nurses' station. When Brackett opens the door and walks out of the base station booth, the actor's T-mark is visible on the floor behind him.
Captain Hook - S6-E8
Visible crew/equipment: After Station 51 is dispatched to "aircraft down," just as the squad and engine roll up on the scene, the reflection of the camera crane can be seen on Engine 51's windshield.
Captain Hook - S6-E8
Visible crew/equipment: When Roy, John, and Chet are standing near the stove talking about Hookrader's party, just as John tells Chet, "And you! You with that speech!" they walk towards the table, and the shadow of the overhead boom mic swoops across the cabinets on the right.
Welcome to Santa Rosa County - S6-E10
Continuity mistake: When getting the climbers off the mountain, the Ford letters on the tailgate are muddy and blanked out, but are not in the scenes where they're transporting the climbers in the pickup bed.
Visible crew/equipment: When Brackett's helicopter takes off the filming helicopter can be seen through the window. (00:03:45)
Continuity mistake: When Roy and Johnny are on the roof with Harriet, we can see the shadow being cast by the utility pole on the street down below, and when the police car shows up moments later that shadow has changed significantly. (00:12:40)
Continuity mistake: After Johnny and Roy bring the injured fireman to the ER, Emma walks up to them in the hallway to ask why they haven't put out the fire yet, and the large handbag hanging from her left arm is suddenly on her right arm when it cuts to the close-up.
Continuity mistake: At the restaurant, when they begin to work on getting Mrs. Merkle out from under the car, Vince sets the Biophone down on the table, and there's a netted, red glass candle on the table, but in a following closeup the candle's net has vanished and it's pinkish clear glass now. Other items on the table change as well.
Continuity mistake: When Brackett tells Dixie about the visiting administrators she's holding a clipboard, but when she's stopped by the man whose son has an arm injury, Dixie's now holding a brown folder.
Revealing mistake: During the rescue at the jail, while Roy tries to get a safety belt around the prisoner's waist, the man freaks out, then grabs Roy and they both swing out on Roy's safety line. When the camera pans a bit too far to the left, we can see the edge of the fake "sky" screen on the left, behind the building's replica set used for closeups.
Continuity mistake: While Brackett is with Ken in the ER he's wearing a blue/white striped tie, and when he calls Ken's doctor the tie is tied differently, but then it's tied the original way.
Continuity mistake: After Johnny and the attendants exit the ambulance with Dora, the pregnant woman, the ambulance is empty and the drug box is on the seat with the Biophone on the floor beside the seat, but in the next shot as the gurney is wheeled inside, the drug box is now on the floor between the Biophone and seat.
Answer: I believe you are speaking of the old man, Mr. Wilson. He's played by J. Pat O'Malley.
Bishop73
Correct, it was J. Pat O'Malley...he also played the grandfather with his grandson when their rocket exploded, and also played "Old Bill" in the episode with Ann Prentiss, where Gage saves the little girl from the burning tree house, and her mother falls in love with him.